System and method for controlling a fuel cell testing device

Abstract

A system and method in a data processor for controlling a controllable condition of a fuel cell via a control device is provided. The system and method involve (a) providing a script language comprising a control command type having an operating level field for receiving a selected operating level of the control device; (b) deriving a control command from the control command type by inserting the selected operating level of the control device into the operating level field of the control command; (c) writing a test script using the script language such that the test script includes the control command; (d) compiling the test script to provide a test program; and, (e) controlling the control device according to the test program.

Description

FIELD OF THE INVENTION

This invention relates to fuel cell testing systems. More particularly, the invention relates to a system for controlling the operation of fuel cell testing systems and for automating fuel cell tests.

BACKGROUND OF THE INVENTION

In recent years, research and development of fuel cells has increased dramatically. It is expected that these efforts will eventually yield commercially viable power systems that produce little pollution.

Fuel cells convert chemical energy stored in fuels into electrical energy. A fuel cell has an anode and a cathode. In some types of fuel cell, hydrogen atoms are introduced into the anode. Within the fuel cell, the hydrogen atoms are separated into electrons and protons (hydrogen ions). The hydrogen ions pass through a membrane to the cathode, where they are combined with oxygen to form water. The electrons cannot flow through the membrane resulting in an electrical potential between the anode and cathode. The electrons flow through an external load to the cathode. Thus, the external load consumes the potential generated by the cell. At the cathode, the hydrogen ions are oxidized to produce water. Theoretically, the only products of the fuel cell are the electrical power consumed by the load, heat and water. In reality, impurities in the hydrogen fuel, environmental conditions and other conditions can substantially effect the efficiency of the fuel cell and resulting in by-products and exhaust products other than heat and water.

A typical fuel cell is capable of producing only a small electrical potential between its anode and cathode—generally about 1 volt. To produce a useful potential individual cells are assembled in series into fuel cell stacks. Typically, a test is conducted on such a fuel cell stack.

Fuel cell stacks must be tested under different and varied conditions to mirror the conditions in which they will be used in practical devices such as motor vehicles. This includes long term test during which conditions change. The development of fuel cells requires substantial testing and several testing systems or “test stations” have been developed for this purpose.

These testing stations allow many conditions of a fuel cell stack, its environment, fuel sources and other conditions to be controlled. Known testing stations allow these conditions to be controlled manually—a target value is set for each condition and automated equipment within the test station attempts to achieve the target value. For example, during a particular test, three target conditions relating to a hydrogen gas supply at the anode fuel supply for a fuel cell may be that it should be supplied at a pressure of 300 kPa, 83° C., and at a rate of 300 lpm (liters per minute). Typical fuel cell testing stations include pumps and flow controllers to achieve the desired pressure and flow rates and heating and/or cooling equipment to achieve the desired temperatures to control the flow rate. Similar characteristics of the cathode gas mixture, the load applied to the fuel cell and other conditions are similarly controllable.

Typically, fuel cell test stations have software control systems. It is preferable that the software has a simple and flexible architecture that allows the control system to be varied and configured easily.

Furthermore, it is desirable that the control system allows fuel cell stacks to be tested substantially automatically. In addition, the control system preferably allows the test or the control system itself to be modified easily—preferably even during a test through modification of the automated test and/or by manually changing the test conditions.

SUMMARY OF THE INVENTION

This invention provides a control system for monitoring and controlling the operation of a fuel cell testing system. The control system itself includes a server that incorporates a system manager and a set of driver applications. Each driver application communicates with a corresponding control module. The control modules in turn communicate with elements of the fuel cell testing system. Each such element may either be controlled or monitored or both by the control module to which it is coupled. For example, flow control elements may be monitored to determine the amount of liquid or gas that is currently flowing through them, and may also be controlled to set the amount of liquid or gas that it will pump.

The driver applications are created and launched by the system manager and they communicate with the system manager through a mapped file created and made available by the system manager. The mapped file contains a record for every controllable or monitorable element in the fuel cell testing system. Elements that are both controllable and monitorable are treated as having separate controllable and monitorable characteristics and each such characteristic has a separate record in the mapped file.

The record for each controllable or monitorable characteristic of an element is identified in the mapped file with a unique tag name. Tags that are associated with a controllable element are referred to as control tags. Tags that are associated with a monitorable element are referred to as data tags.

Tags may be associated by various signal types depending on the nature of the device being controlled or monitored. For example, a valve or switch that may be simply closed or open receives a digital control value to either turn it on or off. The valve or switch can also be queried to determine a digital data value to determine if it is open or closed. The switch has a control tag that is used to transmit the digital control value and has a data tag that is used to query its current state.

In contrast, a flow controller which can be set to allow different controllable amounts of liquid or gas to flow through it will typically receive an analog control value, which defines the amount of gas or liquid that should flow through it. Correspondingly, a flow controller can be queried to determine an analog data value which indicates the amount of liquid or gas that is presently flowing through it. In an alternative embodiment of the present invention a device such as a flow controller having many settings may also receive a digital value consisting of more than one bit that defines a particular setting from the group of settings. For example, an eight bit word may be sent as a control value to instruct the full controller to allow the better gas to flow out one of 256 levels.

Coupled to the system manager is at least one user application that is not part of the first embodiment of the present invention but may be prepared by a user in order to control the operation and procedures of a fuel cell test. The system manager communicates with the driver applications and the one or more user applications through a mapped file. The system manager creates the mapped file and makes it accessible to each driver application and each user application. The mapped file contains tag records and also some system activity info, such as task activity flags that allow the system manager to control the activity of the entire testing system.

Driver applications read the control values of the specific tags and record the present control values. Typically a control module will use a different range of signals to control a physical device then the numerical operating range of that device. For example, a control system may be configured to transmit a signal between 0 to 20 volts to operate a flow controller that is capable of flowing between 0 and 500 standard liters per minute (slpm). The relationship between the 0 and 20 volt input control value range and the 0 and 500 slpm operating level range may or may not be linear. In one embodiment described below it is assumed that the relationship between the ranges is linear. In another embodiment the range may be non linear and the record for the tag in the mapped file may contain either a look-up table or formula or both, which may be used to convert between one range and the other. The record for each tag file contains eight fields to record both the control or data value (depending on whether the tag is a control tag or a data tag) and the current operating level for the tag (which may be a desired operating level for a control tag or an actual operating level for a data tag). The user applications use operating values, which are understood by the humans that will typically use user applications to interact with the fuel cell testing system and the control system of the present invention. User applications use a collection of reading/writing methods (MappedFilesTool.dll) to write or read data in/from the tag file. These reading/writing methods ensure the data converting according to the signal description in each tag.

In accordance with a first aspect of the invention, there is provided a system for testing a fuel cell. The system comprises (a) testing means having a control device for controlling a controllable condition of the fuel cell; (b) a user interface for providing a script language comprising a control command type having an operating level field for receiving a selected operating level of the control device, wherein a test script is writeable using the script language such that the test script includes a control command of the control command type, the control command being derivable from the control command type by inserting the selected operating level of the control device into the operating level field of the control command; (c) a compiler for compiling the test script to provide a test program; and, (d) a system manager for controlling the control device according to the test program.

In accordance with a second aspect of the invention, there is provided a method in a data processor for controlling a controllable condition of a fuel cell via a control device. The method comprises: (a) providing a script language comprising a control command type having an operating level field for receiving a selected operating level of the control device; (b) deriving a control command from the control command type by inserting the selected operating level of the control device into the operating level field of the control command; (c) writing a test script using the script language such that the test script includes the control command; (d) compiling the test script to provide a test program; and, (e) controlling the control device according to the test program.

BRIEF DESCRIPTION OF THE DRAWINGS

A preferred embodiment of the present invention will now be described in detail with reference to the drawings, in which:

FIG. 1 is a schematic illustration of an exemplary fuel cell stack testing system including a control system according to the present invention;

FIG. 2 illustrates the control system of FIG. 1;

FIG. 3 illustrates a start-up method of a system manager of the control system of FIG. 1;

FIG. 4 illustrates a method of operation for driver applications of the control system of FIG. 1;

FIG. 5 illustrates another method of operation for driver applications of the control system of FIG. 1; and,

FIG. 6, in a block diagram, illustrates a system for creating scripts and programs for use by a user application according to a second embodiment of the present invention.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENT

Intro to Fuel Cell Testing Systems

Reference is first made to FIG. 1, which schematically illustrates an exemplary fuel cell stack testing system 100. System 100 has a series of gas inlets 102a, 102b, 102c, . . . , 102g, a de-ionized water input 104, a combustible exhaust outlet 106, a non-combustible exhaust outlet 108, a controllable loadbox 110, a test chamber 112 and a control system 140. Control system 140 is schematically illustrated at several places on FIG. 1 to simplify the Figure.

This exemplary fuel cell testing system 100 is configured for testing hydrogen based fuel cell stacks. When system 100 is in use, a fuel cell stack 114 is usually positioned in test chamber 112. Fuel cell stack 114 has an anode side 114A and a cathode side 114C. The anode side 114A of stack 114 has an anode gas inlet 118A, an anode gas exhaust outlet 120A and an anode electrical terminal 122A. The cathode side 114C has a cathode gas inlet 118C, a cathode gas exhaust outlet 120C and a cathode electrical terminal 122C.

A hydrogen based fuel cell stack typically consists of a stack of individual fuel cells. Stack 114 comprises 8 fuel cells 116a-116h. Each of the fuel cells 116 has an anode side and a cathode side, which are separated by a membrane. (The internal structure of each cell 116 is not shown, but will be well understood by those skilled in the art.) The anode side of each fuel cell is coupled to the anode gas inlet 118A to receive an anode gas mixture. The anode gas mixture includes hydrogen. The cathode side of each fuel cell 116 is coupled to the cathode gas inlet 118C to receive a cathode gas mixture. The cathode gas mixture contains an oxidant. In this exemplary embodiment, the oxidant is oxygen. In this way, hydrogen is supplied to the anode side of each fuel cell 116 and oxygen is supplied to the cathode side. Hydrogen molecules (H2) are separated on the anode side into electrons and hydrogen ions (H+). The hydrogen ions flow across a membrane to the cathode side of the fuel cell 116. The membrane is impermeable to the electrons. Free electrons are collected at an anode current collector. Each cell 116 also has a cathode current collector. The collection of electrons at the anode current collector creates an electrical potential across the fuel cell 116. The fuel cells 116 are electrically arranged in series within the stack 114 so that the combined potential of the fuel cell 116 appears between the anode electrical terminal 122A and the cathode electrical terminal 122C. The electrons freed in each fuel cell 116 flow from the anode electrical terminal 122A through loadbox 110 back to cathode electrical terminal 122C. From the cathode electrical terminals, the free electrons flow to the cathode side of the individual fuel cell 116, where the hydrogen ions, electrons and oxygen combine to form water. The flow of electrons is a current which can perform work in the loadbox 110.

Ideally, stack 114 would receive only hydrogen gas on its anode side and oxygen on its cathode side. However, these ideal conditions are unlikely to be met during the practical usage of a stack. Accordingly, system 100 is configured to provide anode and cathode gas mixtures with controllable compositions. Selected gas inlets 102 are coupled to an anode gas mixture manifold 124 through a series of gas valves 128 and flow controllers 132. Similarly, selected gas inlets 102 are coupled to a cathode gas mixture manifold 126 through a series of gas valves 130 and flow controllers 134. In this exemplary embodiment, the hydrogen, methane, carbon monoxide, carbon dioxide, nitrogen and air supplies (which correspond to gas inlets 102a-102e) are coupled to the anode gas mixture manifold 124 through valves 128a-f and flow controllers 132a-f. The nitrogen, air, oxygen and helox supplies (which correspond to gas inlets 102d-102h) are coupled to the cathode gas mixture manifold 126 through valves 130a-d and flow controller 134a-d.

Gas supply valves 128a-f are controlled by a control system 140 through control lines 129a-f. Gas supply valves 130a-d are controlled by control system 140 through control lines 131a-d. Flow controllers 132a-f are controlled by control system 140 through data/control lines 133a-f. Flow controllers 134a-d are controlled by control system 140 through data/control lines 135a-d. Control system 140 operates valves 128 and flow controllers 132 so that the mixture of gases in anode gas mixture manifold 124 (the “anode gas mixture”) has a selected composition. Similarly control system 140 operates valves 130 and flow controllers 134 to ensure that a cathode gas mixture in cathode gas mixture manifold 126 has a desired composition.

Typically, it is desirable to control the temperature and humidity level of the anode gas mixture and the cathode gas mixture as they are supplied to the stack 114 during a test.

An anode gas heater 136 is coupled to anode gas mixture manifold 124 to monitor the temperature of the anode gas mixture and to heat or cool the anode gas mixture stored in anode gas mixture manifold 124 to a desired temperature. Similarly a cathode gas heater 138 is coupled to cathode gas mixture manifold 126 to monitor the temperature of the cathode gas mixture and to heat or cool the cathode gas mixture to a desired temperature. Anode gas heater 136 is coupled to control system 140 through a data/control line 160, through which control system 140 can monitor the temperature of the anode gas mixture, as well as control the operation of anode gas heater 136.

From anode gas mixture manifold 124, the anode gas mixture passes through an anode gas humidity control unit 144, an anode gas mixture valve 146 and a flow controller 148. From flow controller 148, the anode gas mixture flows into the anode gas inlet 118 of stack 114 through an anode gas reheating jacket 150. From cathode gas mixture manifold 126, the cathode gas mixture flows through a cathode gas humidity control unit 152, a cathode gas mixture valve 156 and a flow controller 156. From flow controller 156, the cathode gas mixture flows through a cathode gas reheating jacket 158 into the cathode gas inlet 118C. The operation of anode gas mixture valve 146 is controlled by control system 140 through control line 172. The operation of anode gas flow controller 148 is controlled by control system 140 through data/control line 174.

During the operation of the system 100, some of the anode gas mixture produced in anode gas mixture manifold 124 is not pumped to stack 114. The excess anode gas mixture is discarded through combustible exhaust outlet 106.

Anode gas heater 136 heats the anode gas mixture to the temperature at which it should be supplied to the stack 114. Reheating jacket 150 ensures that the temperature of the anode gas mixture does not change as the anode gas mixture flows into the stack 114. The operation of anode gas heater 136 (i.e. the temperature to which it heats the anode gas mixture) is controlled by control system 140 through data/control line 160. Similarly, the operation of anode reheating jacket 150 is controlled by control system 140 through control line 162.

System 100 receives a de-ionized water supply at de-ionized water inlet 104. A boiler 176 receives de-ionized water and boils it to produce steam, which is stored in a steam reservoir 178.

Anode humidity control unit 144 receives steam from steam reservoir 178. Anode humidity control unit 144 includes a saturator 164 and a dewpoint controller 162. The anode gas mixture first flows through saturator 164, which is controlled by control system 140 through a data/control line 168. Saturator 164 is typically operated to heat anode gas mixture sufficiently that it becomes completely saturated with water vapour (i.e. it has 100% humidity). From saturator 164, the anode gas mixture flows into dewpoint controller 166, which is controlled by control system 140 via data/control line 170. Dewpoint controller 166 is operated to reduce to the temperature of the anode gas mixture so that the humidity level of the anode gas mixture falls to a desired level. It is not necessary that saturator 164 be operated to completely saturate the anode gas mixture. It is sufficient to heat the anode gas mixture so that its humidity level is at or above the desired humidity level.

The anode gas mixture flows through reheating jacket 150 into an anode gas mixture inlet 118A of stack 114. Some of the anode gas mixture supplied to stack 140 will not be consumed by the anode side of fuel cells 116 and the unused portion of the anode gas mixture is exhausted through anode gas mixture exhaust outlet 120A. From anode gas mixture exhaust outlet 120A, the unused anode gas mixture flows to combustible exhaust outlet 106.

The cathode gas mixture produced in cathode gas mixture manifold 126 is similarly humidified by cathode humidity control unit 152, which has a cathode gas saturator 180 and dewpoint controller 182. The temperature of the cathode gas mixture is controlled by cathode gas heater 138 and cathode reheating jacket 158. The humidification and flow of the cathode gas mixture is controlled by control system 140 through the data/control lines listed in Table 1.

TABLE 1
Data/Control lines for cathode gas related elements
                                Data/control line used by control
                                system 140 to monitor and/or
Element                         control element
Cathode gas heater 138          Data/control line 184
Cathode gas saturator 180       Data/control line 186
Cathode dewpoint controller 182 Data/control line 188
dewpoint controller 154         Data/control line 190
Cathode gas flow controller 156 Data/control line 192
Cathode reheating jacket 158    Data/control line 194

Excess cathode gas mixture that is not pumped to the cathode gas inlet 118C or which is unused and exhausted through cathode gas exhaust outlet 120C is exhausted from system 100 through non-combustible exhaust outlet 108.

During use, stack 114 is typically cooled. De-ionized water from de-ionized water inlet 104 flows into a stack coolant reservoir 196, which has an attached stack coolant cooler 198. Cooler 198 cools the de-ionized water stored in reservoir 196 to a desired temperature. The operation of cooler 198 is controlled by control system 140 through data/control line 200. Cooled de-ionized water flows from reservoir 196 to stack coolant inlet 202, through the stack, stack coolant outlet 204 and back to reservoir 196, under the control of coolant valve 206 and coolant flow controller 208. Coolant valve 206 and coolant flow controller 208 are controlled by control system 140 through data/control lines 210 and 212.

During a test of fuel cell stack 114, it is generally desirable to measure the temperature at various point of system 100 and stack 114. Control system 140 includes thermometers coupled to the points of system 100 and stack 114 listed in Table 2, for measuring the temperature at the indicated points. These thermometers are represented on FIG. 1 by a capital “T” in a circle with an arrow pointing towards the location at which the thermometer takes a measurement. Each of these thermometers is coupled to control system 140, through the data line indicated in Table 2.

TABLE 2
Thermometers coupled to system 100
			Data line coupling
Thermometer		Temperature	thermometer to control
Element No.	Location on FIG. 1	characteristic measured	system 140
214	Stack coolant inlet 202	Temperature of stack	216
		coolant entering stack 114
218	Stack coolant outlet 204	Temperature of stack	220
		coolant exiting stack 114
224	Anode gas inlet 118A	Temperature of anode	226
		gas mixture entering stack
		114
228	Anode gas outlet 120A	Temperature of unused	230
		anode gas mixture exiting
		stack 114
232	Cathode gas inlet 118C	Temperature of cathode	234
		gas mixture entering stack
		114
236	Anode gas outlet 120C	Temperature of unused	238
		cathode gas mixture
		exiting stack 114
240	Stack coolant reservoir	Temperature of stack	242
	196	coolant in reservoir
244	Selected point on stack	Temperature of stack 114	246
	114 (may be moved to	at selected point
	various points on stack)

It is also generally desirable to measure the pressure of the various gases and fluids in system 100 during a test of a fuel cell. Control system 100 includes various pressure sensors coupled to different parts of system 100. Table 3 identifies these pressure sensors and their position in system 100. These pressure sensors are represented on FIG. 1 by a capital “P” in a circle with an arrow pointing towards the location at which the pressure sensor is located and the pressure that it measures. Each of these thermometers is coupled to control system 140, through the data line indicated in Table 3.

TABLE 3
Pressure sensors coupled to system 100
Pressure			Data line coupling
Sensor		Pressure characteristic	pressure sensor to control
Element No.	Location on FIG. 1	measured	system 140
250	Anode gas mixture inlet	Anode gas mixture	252
	118A	pressure at inlet to stack
		114
254	Cathode gas mixture inlet	Cathode gas mixture	256
	118C	pressure at inlet to stack
		114
258	Anode gas mixture outlet	Anode gas mixture	260
	120A	pressure at outlet from
		stack 114
262	Cathode gas mixture	Cathode gas mixture at	264
	outlet 120C	outlet from stack 114
266	Stack coolant inlet 202	Stack coolant pressure at	268
		inlet to stack 114
270	Stack coolant outlet 204	Stack coolant pressure at	272
		outlet from stack 114

One important characteristic of stack performance that is usually measured during a test of a fuel cell stack is the voltage generated between the anode and cathode of each cell in the stack. A set of data lines 280 are coupled between cells 116 and control system 140 to measure the voltage across each cell 116 and to provide the measured voltages to control system 140. A skilled person will recognize that the voltage across a cell 116 will require measurement of the potentials on both sides of the cell 116. Accordingly, each data line 280 may be coupled to a pair of electrodes that are coupled across the cell 116 and a circuit for calculating the voltage difference across the electrodes (such as a differential amplifier) may be used to calculate the voltage value reported to control system 140.

Loadbox 110 is capable of drawing a controlled load from stack 114. The following components of the load drawn by loadbox 110 are configurable: DC power (effectively a current drawn at the power across the stack electrical terminals 122), AC frequency, AC voltage and AC current. Typically, loadbox 110 will be capable of adding any type of AC component into the load on the stack 114. A set of control lines 282-288 are coupled between the loadbox 110 and control system 140 to allow control system 140 to control the different characteristics of the load drawn from stack 114 to be controlled. Control lines 282-288 are described in Table 4.

TABLE 4
Control Lines for Loadbox 110
Control Line Characteristic of load controlled
282          DC power
284          AC current
286          AC voltage
288          AC current

Reference is next made to FIG. 2, which illustrates control system 140, according to a first embodiment of the present invention. Control system 140 includes a server 300, a mapped file 302 and a set of control modules 304a, 304b, 304c, 304d. Server 300 includes a system manager 306 and a set of driver applications 308a, 308b, 308c, 308d.

Control modules 304 are coupled to elements of system 100 (FIG. 1) through the various data/control lines described above. Each of control modules 304 interfaces with different parts of system 100. In this embodiment, control module 304a is a flow control module and, in general, is coupled to valves and flow controllers in system 100. Control module 304b is a thermal control module that is, in general, coupled to thermometers, heaters and coolers in system 100. Control module 304c is a loadbox control module that is, in general, coupled to control lines 282-288 to control the operation of loadbox 110. Control module 304d is a Fuel Cell Voltage Monitoring (FCVM) control module that is coupled to the control lines 280, which monitor the voltage across fuel cell 116 in stack 114. Each control module 304 is coupled to system manager 306 through a corresponding driver application 308.

Communications between each control module 304 and its corresponding driver application will be carried out using a selected communications protocol. For example, protocols such as RS232, RS485, IEEE488 or any other serial or parallel data communication protocol may be used. The selection of the protocol will typically depend on the nature of the devices included in the control module.

In this embodiment, communications between each driver application 308 and the system manager 306 are accomplished using a pair of message queues. To communicate with system manager 306, driver application 308a stores messages in a shared memory. System manager 306 subsequently retrieves the messages from the shared memory and acts on them. To communicate with driver application 308a, system manager 306 stores messages in the shared memory. Driver application 308a subsequently retrieves and acts on the messages. Driver applications 308b-d similarly use the shared memory to communicate with system manager 306. In other embodiments, communication between the driver applications 308 and system manager 306 may be performed using any known mechanism, such as message queues or another communication techniques.

Table 5 describes the following characteristics of each of the data/control lines coupled to system 100:

TABLE 5
Data/Control lines and associated tag information
	Field in Table 5	Description
	Data/Control	The reference numeral used to identify the data/control
	Line	line in this patent.
	Element	The reference numeral used to identify the element of
		system 100 that is monitored or controlled or both using
		the identified data/control line.
	Tag name	A unique reference name for the specific characteristic
		controlled.
	Signal Type	The type of communication signal transmitted across the
		data/control line. A digital signal is typically used to switch
		a device on or off. An analog signal is used for devices
		that can be set at multiple levels, or at any level between
		some low and high limits.
		A digital value signal is used to transmit a digital word
		encoding a control or data level. For example, an 8 bit
		digital word may be used to encode a digital value signal
		that may have up to 256 levels.
		An output signal is used to control a device - the device is
		set to operate at the specified controlled level by sending
		a signal through the associated control line. Tags relating
		to an output signal are referred to as “control tags”.
		An input signal is used to monitor a device - the current
		operational level of the device is reported through the data
		line. Tags relating to an input signal are referred to as
		“data tags”.
		Some data/control lines are data lines only. Such data
		lines are used to monitor an element of system 100.
		Other data/control lines are control lines only. These
		control lines are used only to control an element of system
		100. Other data/control lines operate bi-directionally and
		allow both data and control signals to be transmitted.
		These bi-directional data/control lines may consist of a
		single physical line or may consist of multiple physical
		lines which separately carry the data and control
		communications.
	Module	The name of the control module to which the data/control
		line is connected.
	Tag #	A unique tag number that allows the tag to be identified.
	Control/Data	Used for analog inputs and outputs. Defines the lowest
	Range Low	control or data signal level use by the associated control
		module to communicate with a device (for the specified
		tag). For example, flow control module 304a transmits an
		analog signal to flow controller 134a, which controls the
		flow of helox gas into the cathode gas mixture manifold
		126, using data/control line 135a. The analog signal has a
		range between 0 to 20. The units of this range will depend
		on the interface used by the associated flow control device
		304. For example, a signal of between 0 to 20 volts may
		be used. Alternatively, a signal of between 0 to 20
		milliamps might be used. The present invention is not
		limited to the use of any particular control interface
		between a device and the associated control module.
	Control/Data	Used for analog inputs and outputs. Defines the highest
	Range High	control or data signal level use by the associated control
		module to communicate with a device.
	Device	Used for analog inputs and outputs. Defines the lowest
	Operating Range	operational level for an element of system 100. A device
	Low	will typically receive control signals or transmit data signal
		within its control/data range that correlate to its operational
		range. Typically, the two ranges will be different. For
		example, flow controller 134a receives control signals
		ranging between 0 and 20. However, it is capable of
		pumping between 0 to 500 standard liters per minute (see
		Units field) of helox into the cathode gas mixture manifold.
		In this embodiment, the relationship between the control
		range and the operational range is assumed to be linear.
		In other embodiments, the relationship may be non-linear
		and may be different for different devices. The tag file
		may be modified to include co-efficients defining a non-
		linear relationship between the control/data range and the
		operating range. Such co-efficients may define an
		algebraic conversion, a lookup table or a combination of
		these and possibly other mechanisms for converting
		between the control/data range and the operational range.
	Device	Used for analog inputs and outputs. Defines the highest
	Operating Range	operational level of an element of system 100.
	High
	Units	The name of the unit in which the operational range of the
		device is defined.
Data/						Control	Control	Device	Device
Control						Range	Range	Range	Range
Line	Element	Tag name	Signal Type	Module	Tag#	Low	High	Low	High	Units
129a	128a	Valve_anode_mix_H2	Digital output	Flow Control	661	—	—	—	—	—
129b	128b	valve_anode_mix_ch4	Digital output	Flow control	666	—	—	—	—	—
129c	128c	valve_anode_mix_co2	Digital output	Flow control	663	—	—	—	—	—
129d	128d	valve_anode_mix_co	Digital output	Flow control	664	—	—	—	—	—
129e	128e	Valve_anode_mix_N2	Digital output	Flow control	662	—	—	—	—	—
129f	128f	valve_anode_mix_air	Digital output	Flow control	665	—	—	—	—	—
131a	130a	valve_cathode_mix_helox	Digital output	Flow control	680	—	—	—	—	—
131b	130b	valve_cathode_mix_o2	Digital output	Flow control	677	—	—	—	—	—
131c	130c	valve_cathode_mix_air	Digital output	Flow control	676	—	—	—	—	—
131d	130d	valve_cathode_mix_N2	Digital output	Flow control	678	—	—	—	—	—
133a	132a	flow_anode_mix_H2	Analog Input	Flow control	576	0	20	0	300	Slpm
		flow_anode_mix_h2_set	Analog output	Flow control	577	0	20	0	300	Slpm
133b	132b	flow_anode_mix_ch4	Analog Input	Flow control	586	0	20	0	50	Slpm
		flow_anode_mix_ch4_set	Analog output	Flow control	587	0	20	0	50	Slpm
133c	132c	flow_anode_mix_co2	Analog Input	Flow control	580	0	20	0	300	Slpm
		flow_anode_mix_co2_set	Analog output	Flow control	581	0	20	0	300	Slpm
133d	132d	flow_anode_mix_co	Analog Input	Flow control	582	0	20	0	1000	Slpm
		flow_anode_mix_co_set	Analog output	Flow control	583	0	20	0	1000	Slpm
133e	132e	flow_anode_mix_N2	Analog Input	Flow control	578	0	20	0	500	Slpm
		flow_anode_mix_n2_set	Analog output	Flow control	579	0	20	0	500	Slpm
133f	132f	flow_anode_mix_air	Analog Input	Flow control	584	0	20	0	50	Slpm
		flow_anode_mix_air_set	Analog output	Flow control	585	0	20	0	50	Slpm
135a	134a	flow_cathode_mix_helox	Analog Input	Flow control	614	0	20	0	500	slpm
		flow_cathode_mix_helox_set	Analog output	Flow control	615	0	20	0	500	slpm
135b	134b	flow_cathode_mix_o2	Analog Input	Flow control	608	0	20	0	50	slpm
		flow_cathode_mix_o2_set	Analog output	Flow control	609	0	20	0	50	slpm
135c	134c	flow_cathode_mix_air	Analog Input	Flow control	606	0	20	0	50	slpm
		flow_cathode_mix_air_set	Analog output	Flow control	607	0	20	0	50	slpm
135d	134d	flow_cathode_mix_N2	Analog Input	Flow control	610	0	20	0	500	slpm
		flow_cathode_mix_n2_set	Analog output	Flow control	611	0	20	0	500	slpm
170	166	signal_out_anode_dewpt_loop	Digital output	Flow control	747	—	—	—	—	—
168	164	temp_anode_sat	Analog Input	Thermal	512	0	1000	0	100	° C.
				control
		temp_anode_sat_set	Analog output	Thermal	513	0	1000	0	100	° C.
				control
170	166	temp_anode_dewpt	Analog Input	Thermal	516	0	1000	0	100	° C.
				control
		temp_anode_dewpt_set	Analog output	Thermal	517	0	1000	0	100	° C.
				control
131	130	valve_anode_stack	Digital output	Flow control	692	—	—	—	—	—
174	148	flow_anode_stack	Analog Input	Flow control	638	0	20	0	11	slpm
		flow_anode_stack_set	Analog output	Flow control	639	0	20	0	11	slpm
162	150	signal_out_anode_reheat_loop	Digital output	Flow control	748	—	—	—	—	—
162	150	temp_anode_reheat	Analog Input	Thermal	520	0	1000	0	100	° C.
				control
		temp_anode_reheat_set	Analog output	Thermal	521	0	1000	0	100	° C.
				control
216	214	temp_anode_inlet	Analog Input	Thermal	524	0	1000	0	100	° C.
				control
		temp_anode_inlet_set	Analog output	Thermal	525	0	1000	0	100	° C.
				control
188	182	signal_out_cathode_dewpt_loop	Digital output	Flow control	749	—	—	—	—	—
226	224	temp_anode_out	Analog output	Flow control	542	0	0	0	0	° C.
192	156	signal_out_cathode_reheat_loop	Digital output	Flow control	750	—	—	—	—	—
188	182	temp_cathode_dewpt	Analog Input	Thermal	518	0	1000	0	100	° C.
				control
		temp_cathode_dewpt_set	Analog output	Thermal	519	0	1000	0	100	° C.
				control
186	180	temp_cathode_sat	Analog Input	Thermal	514	0	1000	0	100	° C.
				control
		temp_cathode_sat_set	Analog output	Thermal	515	0	1000	0	100	° C.
				control
194	158	temp_cathode_reheat	Analog Input	Thermal	522	0	1000	0	100	° C.
				control
		temp_cathode_reheat_set	Analog output	Thermal	523	0	1000	0	100	° C.
				control
242	240	temp_coolant_tank_out	Analog Input	Thermal	528	0	1000	0	100	° C.
				control
		temp_coolant_tank_out_set	Analog output	Thermal	529	0	1000	0	100	° C.
				control
190	154	valve_cathode_stack_1	Digital output	Flow control	697	—	—	—	—	—
252	250	pressure_anode_in	Analog Input	Flow control	806	1	5	0	350	kPa
		pressure_anode_in_set	Analog output	Flow control	807	4	20	0	350	kPa
256	254	pressure_cathode_in	Analog Input	Flow control	808	1	5	0	350	kPa
		pressure_cathode_in_set	Analog output	Flow control	809	4	20	0	350	kPa
260	258	pressure_anode_diff	Analog Input	Flow control	810	0	5	0	35	KPa
264	262	pressure_cathode_diff	Analog Input	Flow control	811	0	5	0	35	KPa
268	266	pressure_coolant	Analog Input	Flow control	812	4	20	0	550	KPa
		pressure_coolant_set	Analog output	Flow control	813	0	0	0	0	KPa
272	270	pressure_coolant_diff	Analog Input	Flow control	814	0	5	0	100	KPa
220	218	temp_cathode_inlet	Analog Input	Thermal	526	0	1000	0	100	° C.
				control
		temp_cathode_inlet_set	Analog output	Thermal	527	0	1000	0	100	° C.
				control
192	156	flow_cathode_stack_1	Analog Input	Flow control	648	0	20	0	10	Slpm
		flow_cathode_stack_1_set	Analog output	Flow control	649	0	20	0	10	Slpm
234	232	temp_cathode_out	Analog output	Flow control	544	0	0	0	0	° C.
246	244	temp_stack_control	Analog Input	Thermal	530	0	1000	0	100	° C.
				control
		temp_stack_control_set	Analog output	Thermal	531	0	1000	0	100	° C.
				control
200	198	signal_out_coolant_heater	Digital output	Flow control	752	—	—	—	—	—
210	196	signal_out_coolant_pump	Digital output	Flow control	751	—	—	—	—	—
212	208	flow_stack_coolant	Analog Input	Thermal	658	0	500	0	50	Lpm
				control
		flow_stack_coolant_set	Analog output	Thermal	659	0	500	0	50	Lpm
				control
280a	116a	data_cell_001	Analog Input	FCVM (Fuel	0	0	5	0	5	V
				Cell Voltage
				Monitor)
280b	116b	data_cell_002	Analog Input	FCVM	1	0	5	0	5	V
280c	116c	data_cell_003	Analog Input	FCVM	2	0	5	0	5	V
280d	116d	data_cell_004	Analog Input	FCVM	3	0	5	0	5	V
280e	116e	data_cell_005	Analog Input	FCVM	4	0	5	0	5	V
280f	116f	data_cell_006	Analog Input	FCVM	5	0	5	0	5	V
280g	116g	data_cell_007	Analog Input	FCVM	6	0	5	0	5	V
280h	116h	data_cell_008	Analog Input	FCVM	7	0	5	0	5	V
282	110	Lb_DC_volts	Digital value	Loadbox	843	0	1	0	1	V
			output
284	110	Lb_AC_Freq	Digital value	Loadbox	848	0	10000	0	10000	Hz
			output
286	110	Lb_AC_Volts	Digital value	Loadbox	849	0	1000	0	1000	A
			output
288	110	Lb_AC_Amps	Digital value	Loadbox	850	0	1000	0	1000	V
			output

A tag file 310 is stored on a storage device 312 which is accessible to server 300. Tag file 310 contains the information shown in Table 5 for each tag, with the exception of the associated data/control line number and the element number. The use of tag file 310 is explained below.

System manager 306 and driver applications 308 are separate threads of execution (and may be running on the same computer). System manager 306 operates mapped file 302 which contains information relating to every monitorable or controllable element in system 100.

Reference is next made to FIG. 3, which illustrates a method 1100 by which system manager 306 initiates the operation of system 100.

Method 1100 begins in step 1102 in which system manager 306 reads tag file 310. System manager 306 then creates mapped file 302 in a local memory space in step 1104. Mapped file 302 contains a record for each tag in tagged file 310 containing all of the fields that are in the tagged field, as well as two additional fields:

• • 1. A control/data value field—which contains the current control value for a control tag, or the current data value for a data tag. The values in this field are in the same units as the control/data range for each device.
  • 2. An operating level field—which contains a value corresponding to the control/data value, but in the same units as the operating range for the device.

By way of example, consider the operation of method 1100 relative to tags 576 and 577. In step 1102, system manager 306 reads tag file 310. System manager 306 then creates a mapped file 302 in a local memory space, which mapped file 302 contains a record for tags 576 and 577. This record includes all of the fields for tags 576 and 577 that are in tag file 310, and also includes, for tag 576, a data value field containing the current data value for tag 576, and, for tag 577, a control value field containing the current control value for tag 577. In addition, mapped file 302 contains an operating level field for each of tags 576 and 577, which includes the information stored in the data and control value fields respectively, converted to the same units as the operating range for the device.

Method 1100 then proceeds to step 1106. In step 1106, system manager 306 initiates a driver application for each flow control module. In this embodiment, system manager 306 determines which control modules 304 are present in control system 140 based on the entries in the Module field of the tagged file 310. Alternatively, a list of the control modules 304 may be provided to system manager 306 in a data file, or system manager 306 may analyze the hardware coupled to control system 140 and system 100 to determine which control modules are present.

In this embodiment, four control modules are installed: flow control module 304a, thermal control module 304b, loadbox control module 304c and FCVM control module 304d. In response, system manager 306 initiates four driver applications 308a-308d. Each of these driver applications is an independent thread of execution and operates independently of the others. When initiating each driver application 308, system manager creates the associated message queues (i.e. message queues 316 and 318 for driver application 308a).

System manager 306 then proceeds to step 1108, in which it initiates one or more user applications 314, if any user applications are installed in system 100. The purpose and operation of user applications is discussed below. Such user applications are not part of this first exemplary embodiment of the present invention, although they are included in other embodiment described below. System manager 20 then proceeds to step 1110.

Step 1110 is an optional step which may or may not be included in different embodiments of the present invention. In this step, system manager 306 reads an initial conditions data file (not shown) from a storage device. The initial conditions data file identifies one or more control tags and sets out an initial value for the control tag. For each identified control tag, system manager 306 enters the specified initial value in the control/data value field of the tag's record in the mapped file. System manager 306 then converts the control/data value into the corresponding operating level and stores the result in the operating level field of the tag's record in the mapped file. (Alternatively, the initial value data file may specify a tag's initial operating value and system manager 306 may calculate the corresponding data/control value.)

At the end of step 1110, the initialization operations of system manager 306 are complete. System manager 306 then enters a loop and remains in this loop indefinitely during a fuel cell test. The loop begins in step 1110.

Before describing this loop, it is desirable to explain the purpose and operation of driver applications 308 and user applications 314. Each driver application 308 interfaces with one or more control modules, which provide an interface with the control and data collection devices in system 100. Each driver application must have access to the relevant tag records in mapped file 302, in which the desired and actual operational conditions of system 100 are recorded.

For example, driver application 308a uses flow control module 304a to control the operation of flow controller 132a, which controls the flow rate of hydrogen into the anode gas mixture manifold 124. Driver application 308a can query flow controller 132a to determine the current flow rate of hydrogen in anode gas mixture manifold 124. The flow rate reported in response to such a query should be recorded in the control/data value field for the tag flow_anode_mix_H2 (tag No. 576 in Table 5) in mapped file 302. Driver application 308a can also instruct flow controller 132a to change the flow rate of hydrogen into anode gas mixture manifold 124 to a specified level. This specified level is recorded in the control/data value field for the tag flow_anode_mix_H2_set (tag No. 577 in Table 5) in mapped file 302. Driver application 308a can similarly query the operational conditions for all elements of system 100 from which it can receive an input signal (i.e. a digital or analog input) signal and can control the operational settings for any elements to which it can send an output signal.

Each driver application 308 accesses mapped file 302 through system manager 306 by sending messages to and receiving messages from system manager 306 using a pair of message queues. To facilitate this, each driver application uses a method class containing the methods set out in Table 6. Each of the methods transmits a message to system manager 306 and, if appropriate, system manager 306 transmits a return message. The method reads the return message and returns any return values to the driver application.

TABLE 6
Methods in method class accessing mapped file 302
			Operation performed by
			system manager 306 or by
Method Name	Input Values	Return Values	user application 314	Comments
InitializeAndOpen		Handle for mapped	Provides handle, which, in	Allows mapped file 302 to
MappedFile		filed 302	turn provides access to	be created and opened with
			mapped file 302	the provided handle.
			To be used by only the
			system manager
OpenMappedFile	Mapped file	Handle for mapped	Provides read/write access	Allows mapped file 302 to
	name	filed 302	to mapped file	be opened
CloseMappedFile	Mapped file		Terminates read/write	Allows mapped file 302 to
	handle		access to mapped file	be closed.
ReadTaggedValue	Tag number	Current	Provides current	Returns current specified
		control/data value	control/data value (first	control value (for a control
		for tag (first among	among 5 values) for	tag) or currently recorded
		5 values)	identified tag in mapped file	operating value (for a data
		−1 if there is no	302. Used by user	tag) for a tag.
		mapped file	applications. Applies data
		available	conversion.
WriteTaggedValue	Tag number,	Write confirmation	Records new control/data	Allows new desired control
	new	(FALSE if there is	value (first among 5 values)	value for a control tag.
	control/data	no mapped file	for tag in tag's record in
	value for tag	available, or wrong	mapped file 302.
	(first among 5	tag number)	Used by user applications.
	values)		Applies data conversion.
ReadTaggedValues	Tag number	Pointer to the	Provides current	Allows reading all the 5
		current control/data	control/data values (5	possible current values of
		values (5 possible	values) for the identified tag	the tag.
		values) for each	in the mapped file 302
		identified tag
		Returns −1 if there
		is no mapped file
		available.
WriteTaggedValues	Tag number,	Write confirmation	Records new control/data	Allows writing all the 5
	new	(FALSE if there is	values (5 possible values)	possible values of a tag.
	control/data	no mapped file	for the identified tag in the
	values (	available, or wrong	mapped file 302
	pointer to a 5	tag number)
	elements
	array)
GetDataArray	Starting tag,	Pointer to an array	Provides current	Allows reading the first
	number of	containing the	control/data value (first	current value for more than
	tags	current control/data	value) for a number of tags	one tag at a time.
		value (first value)	from the mapped file
		for each identified	302starting with the one
		tag	mentioned as first
SetDataArray	Starting tag,	Write confirmation	Records current	Allows writing the first
	number of	(FALSE if there is	control/data value (first	current value for more than
	tags, pointer	no mapped file	value) for a number of tags	one tag at a time.
	to an array,	available, or wrong	of the mapped file 302,
	containing	tag specification)	starting with the one
	the current		mentioned as first
	values (first
	value) of all
	mentioned
	tags
GetTagInfo	Tag number	Pointer to an array	Provides the information	Allows the user application
		containing tag	describing a tag (tag name,	or the drivers to access the
		description	tag type, module, module	tag description.
		information	address, channel number..)
SetTagInfo	Tag number,	Write confirmation	Records changes of the tag	Allows changes of the tag
	Pointer to an	(FALSE if there is	description.	description —not
	array	no mapped file		recommended to be
	containing	available, or wrong		frequently used.
	tag	tag number)
	description
	information
GetTaggedFullValue	Tag number	Control/Data	Provides control/data range	Allows reading tag specific
		Range High field	high value for tag from tag's	info
		value for the tag	record in mapped file 302
GetTaggedZeroValue	Tag number	Control/Data	Provides control/data range	Allows reading tag specific
		Range Low field	low value for tag from tag's	info
		value for tag	record in mapped file 302
GetTaggedRangeHigh	Tag number	Device Operating	Provides operating range	Allows reading tag specific
		Range High for tag	high value for tag from tag's	info
			record in mapped file 302
GetTaggedRangeLow	Tag number	Device Operating	Provides operating range	Allows reading tag specific
		Range High for tag	low value for tag from tag's	info
			record in mapped file 302
GetTaggedCoefficients	Tag number,	Read confirmation	Provides the value of the 6	Allows reading tag specific
	pointer to an	(FALSE if there is	calibration coefficients.	info
	array of 6	no mapped file
	possible	available, or wrong
	integer	tag specification)
	values
GetTagIndex	Tag name	Tag index, or −1	Provides the tag number of	Allows determining the tag
		FALSE if there is	the named tag	number of a named tag.
		no mapped file
		available, or wrong
		tag name
		specification)
TaskCheckIn	Task name	ID number	Used by user applications	Check in procedure to allow
			and driver applications at	the system manager to
			start to notify their start and	control the task activity.
			get an ID
TaskCheckOut	Task ID		Used by user applications	Check out procedure to
			and driver applications	allow the tasks to notify the
			before ending to notify their	system manager about their
			normal stop.	normal stop.
TaskUpdateTaskActivity	Task ID		Used by user applications	Allows the system manager
			and driver applications to	to periodically notice that
			periodically update a	the task having the
			designated activity flag	specified ID is still alive.
				The designated activity flag
				is cleared by the system
				manager each checking
				time.
TaskCheckServerActivity		TRUE if the system	Used by user applications	Allows the user applications
		manager activity	and driver applications to	and driver applications to
		flag is set, FALSE	periodically check if the	periodically check if the
		otherwise	system manager is still alive	system manager is still
				running.

Using the methods in the method class set out in Table 6, driver applications 308 are able to read and write control/data values from and to mapped file 302. Typically, driver applications 308 read control values from the records of control tags and write data values into the records of data tags. The control values are used to control the elements of system 100 and the data values report the operational states of the elements of system 100.

User applications 314 are used to define the desired operational state of system 100 during a fuel cell test, or during operation of system 100 at any time, and to report the operational state of system 100 to a user. User applications may be: user interfaces that allow the user to “manually” set the desired operational characteristics of system 100 and that display the current operational state; fully automated software programs that define a fuel cell test and have data recording capabilities for recording the performance of system 100 during the test, a combination of such manual and automated software or other types of program.

User applications 314 provide operating level values for recordal into control tags and read operating level values from data tags for reporting to a user, either through a user interface, data file, both a data file and a user interface or through another reporting device (i.e. a printer), transmitting an e-mail message, wireless pager or other communication device, etc. For control tags, user applications 314 provide operating level values, and the writing method covert them into control value and record them in mapped file. For data tags, the reading methods return the operating level value for the specified tag.

Several user applications 314 are described below in association with other embodiments of the present invention. For the purposes of this embodiment, it suffices that user applications 314 of any nature provide control value and, optionally, read data values from the records of control tags and data tags in mapped file 302.

User applications 314 may access the mapped file 302 in the same way as the driver applications 308: by using the methods in the method class set out in Table 6.

Both user applications and driver applications should access at the start the mapped file in order to apply a “check in” procedure. This procedure consists in specifying its own name and getting back an assigned ID to be used further on to periodically update a designated activity flag—activity update procedure. This procedure serves to have the system manager check if the applications involved in the testing system are “still alive”. The user applications can also determine if the system manager is “still alive” by checking its own activity flag. Each application before stopping has to apply a “check out” procedure to let the system manager know that it is not active anymore. Specific methods in the method class set out in Table 6 are used.

The system manager periodically accesses the mapped file to update its own activity flag and check the running user applications and driver applications activity flags, by using the specific methods in the method class set out in Table 6.

Typically, the user application writes control values to the records of control tags and reads data values from the records of data tags. The control values are then read by driver applications 308 to control the components of system 100 through control modules 304. The data values read by user applications 314 from the records of mapped file 302 will typically have been written into the mapped file by driver applications 308a.

System manager 306 requires each driver application 308 to periodically update a designated activity flag in the mapped file. This ensures that a driver application that has stopped executing properly is detected and allows the system manager 306 to take corrective action, which may include stopping and restarting the driver application, terminating any fuel cell test then underway, or taking other action. System manager 306 also requires that all user applications 314 that have applied the check-in procedure to similarly indicate that they are executing properly.

In other embodiments, method 1100 may have additional steps. For example, in some other embodiments, system manager 306 may require each driver application 308 to transmit at least one message within a selected time of its previous message to system manager 306. An additional method to send such an “I'm alive” message may be added to the method class of Table 6 for this purpose. This ensures that a driver application which has stopped executing properly is detected and allows system manager 306 to take corrective action, which may include stopping and restarting the driver application, terminating any fuel cell test then underway, or taking other action. System manager 306 may also require user applications 314 to similarly indicate that they are executing properly.

Driver applications 308 use and update the data recorded in mapped file 302. Each driver application obtains a handle for the mapped file 302 that system manager 306 is using by using the InitializeAndOpenMappedFile method.

Reference is next made to FIG. 4, which illustrates a method 1200 by which each driver application 308 controls the element of system corresponding to each tag that the driver application is associated with in Table 5. Each driver application 308 is coupled to a control module to monitor and/or control the operation of at least one element of system 100. Each characteristic that is monitored corresponds to a data tag in the tagged file and in the mapped file 302. Each characteristic that is controlled corresponds to a control tag in the tagged file and in the mapped file 302. The driver application may be said to be associated with each such data and control tag.

Method 1200 is executed by a driver application 308 in respect of each control tag that it is associated with. Method 1200 begins in step 1202, in which the driver application 308 uses the ReadTaggedValue method to obtain the current control value (from the control/data value field of the mapped file) for the control tag. For example, driver application 308a may use the ReadTaggedValue to obtain the current control value for the flow_cathode_stack_—1_set tag (tag No. 531 in table 5) to determine what flow rate has been specified for the flow of the cathode gas mixture into the stack (by a user application).

Method 1200 next proceeds to step 1204 in which the driver application transmits the control value for the control tag to its associated control module. Using the example above in step 1202, driver application 308a would transmit the control value to flow control module 304a. Flow control module 304a would then use the control value to control the operation of flow controller 156 by sending control signal on data line 192 (see FIG. 1 and Table 5). The nature of the control signal sent by the control module to the attached element of system 100 will depend on the particular element. For example, a flow controller may be controlled by a high quality PID type feedback control device that monitors and controls the operation of the flow controller constantly to ensure that the flow rate accurately tracks the specified flow rate.

Method 1200 next proceeds to step 1206 in which the driver application waits for a selected time period. The selected time period depends on the particular tag for which method 1200 is being performed. For example, when controlling a flow controller 132 to control the different concentrations of gases in the anode gas mixture, driver application may have a short delay to ensure that changes in the concentrations are processed quickly after they are made by user applications. On the other hand, the delay between iterations of the method 1200 for flow controller 208 may be longer. These comparisons are merely exemplary and in an actual embodiment of the present invention, the delays will be selected based on the type of elements being controlled and the desired degree of precision, as well as the limitations of the associated control module.

After step 1206, method 1200 returns to step 1202.

Reference is next made to FIG. 5, which illustrates a method 1300 by which each driver application 308 monitors the operation of each system element corresponding to each data tag with which the driver application is associated in Table 5. Method 1300 is executed by a driver application 308 in respect of each data tag with which it is associated.

Method 1300 begins in step 1302, in which the driver application 308 queries its associated control module as to the current operating level of the element of system 100 corresponding to the tag for which method 1300 is being performed. For example, driver application 308a may query flow control module 304 to obtain the current flow rate of the cathode gas mixture into the stack 116. This operational level is the data value for the data tag.

Method 1300 next proceeds to step 1304, in which driver application writes the data value to the mapped file record for the tag using the WriteTaggedValue method.

Method 1300 next proceeds to step 1306, in which driver application waits a selected time.

Method 1300 then returns to step 1302.

Using method 1200, each driver application 308 periodically reads the control value for each control tag with which it is associated and transmits the control value to the corresponding element of system 100. Similarly, using method 1300, each driver application 308 periodically obtains the data value for each data tag with which it is associated and stores the data value in the mapped file. Methods 1200 and 1300 are performed simultaneously by each driver application 308 for all control and data tags with which the driver application 308 is associated.

Using these methods, control system 140 controls and monitors each characteristic of each element of system 100 for which a tag has been added to the mapped file. Control system 140 attempts to control system 100 in accordance with the control/data value recorded in the mapped file 302 by a user application. Control system 140 makes the current operational state of the system 100 conform to user applications by updating the data tags in mapped file 302.

Before launching driver applications, the system manager configures them according to the tag file description of the control modules and elements of the current tested system.

Control system 140 has been described in the context of a simplified fuel cell testing system 100. Other embodiments of control system 140 may include data/control lines, tags, control modules and other elements, depending on the structure of the associated fuel cell testing system. Several such variations are described below. A skilled person will be capable of adding control/data lines, tags, control modules and elements to system 100 to accommodate the described variations.

For example, other embodiments of the present invention may include sources of other gases, or may include fewer gases to choose from that may be used to produce the anode gas mixture and/or the cathode gas mixture. Such an embodiment will include corresponding control/data lines to control the flow of such gases, tag lines and entries in the mapped file.

According to different embodiments of the present invention, the stack may include any number of fuel cells. The corresponding control system will include corresponding control/data lines to monitor the voltage across each cell in the stack.

Other embodiments of the invention may include controlling and monitoring the environment chamber in which the fuel cell stack is situated during a fuel cell test. For example, the humidity and temperature of the environment chamber may be controlled. Such embodiments will include control tags in the mapped file for control values associated with the temperature and humidity as well as corresponding data tags for monitoring the temperature and humidity. A skilled person will be capable of providing the appropriate data and control lines for such an embodiment.

Other embodiments of the invention may include data tags for monitoring the coolant fluid as well as the anode and cathode mixtures. Such data tags will be associated with appropriate data lines coupled to two sensors in the fuel cell testing system.

Other embodiments may include valves and full meters as well as pressure sensors for controlling and monitoring the main gas supply as well as the gas exhaust outlets. Such systems will include appropriate control and data tanks as well as the appropriate control and data lines in associated hardware within the fuel cell testing system.

The foregoing characteristics are only a sample of the test conditions that may need to be controlled during the testing of a particular fuel cell for a particular purpose. The present invention provides a software system for controlling system 100 to regulate these conditions, as well as other conditions, based on the particular of the fuel cell testing system with which the present invention is used.

Reference is made to FIG. 6. A second exemplary embodiment of the present invention will now be described. The second embodiment is identical in structure to the first exemplary embodiment described above with the addition of system 400 for creating user applications. System 400 includes a scripting language 402, a script compiler 404 and a program processor 406. Program processor 406 is a user application 314 (See FIG. 2).

Scripting language 402 is used to create scripts 408 for conducting fuel cell tests using system 100 (FIG. 1). Scripting language 402 has a number of commands, which are set out in Tables 7-11. Scripts 408 are converted into programs 410 using script compiler 404. While doing so, script compiler 404 checks the syntax and flow of the script 408 to ensure that an executable program 410 can be assembled. Executable programs 410 are used by program processor 406 to communicate with system manager 306 to control a fuel cell test.

Table 7 describes a set of setpoint commands which are used in a script to set the desired operating level for a device associated with a control tag. The parameters for each setpoint command are described in Table 7.

TABLE 7
Setpoint Commands
Command	Parameters	Description
Set_flow	Tag#, Flow, Ramp	Valid only for control tags for flow controllers. The flow rate of the
		specified flow controller (based on the tag#) is changed to the
		specified flow rate. The flow rate is changed at the ramp rate. For
		example, if the tag No. = 583, Flow = 200 and Ramp = 25, then the
		flow rate of flow controller 132d is changed from its current flow rate to
		200 slpm at a change of 25 slpm/second (or other selected time
		period).
Set_stoich	Tag# and	Helps to control the gas flow. That is, the gas flow is calculated using
	stoichiometric ratio	stoich and load current.
Set_load	Tag#, characteristic,	Valid only for loadbox tags. Characteristic may be set out in volts (DC
	Ramp	or AC volts), Hz (AC frequency) or amps (AC current). Ramp defines
		the rate of change of the characteristic from the current control value.
Set_temperatue	Tag#, Temp, Ramp	Valid only for control tags for temperature controls (i.e. heaters,
		coolers, etc.) The temp parameter defines the new target temperature
		and the ramp field defines the desired rate of change from the old
		target temperature to the new target temperature
Set_pressure	Tag#, Pressure, Ramp	Valid only for control tags for pressure controls. A pressure controller
		(not shown) provides distributed pressure control via individual
		pressure control devices (not shown) distributed in the fuel cell testing
		system.
Set_equivalent_flow	Tag#, Flow and Ramp	Used for the calculation of flow. It calculates the proper gas flow
		setpoint according to the load current and the stoich.
Get_tag_value	Tag#, Value	This command is used to read tags.

Table 8 describes a series of commands that apply to system 100, including control system 140.

TABLE 8
Test System Action Commands
Command              Description
Start_averaging      In some embodiments of the present
                     invention, control system 140 is configured to
                     average the operating level field for all data
                     tags defined in the map file. This command
                     initiates this averaging operation.
Stop_averaging       This command terminates the averaging
                     operation. The results of the averaging
                     operation are recorded in a log file.
                     Alternatively, the record for each data tag in
                     the mapped file may include an “Average
                     value” field, in which the average operating
                     level during the last averaging operation is
                     stored.
Enable_safeties      Tells system to conduct safety check.
Override_safeties    Overrides instructions to conduct safety
                     check.
E_stop               Emergency stop of test.
Clear_alarms         Clears alarm messages.
Log_data_now         The records of all tags in the mapped file are
                     recorded in a log file.
Log_data_subset      The records of a set of tags previously
                     associated with the subset_no is added to a
                     log file.
Start_new_datafile   The log file used for the Log_data_now and
                     Log_data_subset commands is closed and a
                     new datafile is opened.
Autologging_ON       Automatic logging of changes in tag records in
                     the mapped file to the log file is turned on.
Autologging_OFF      Automatic logging of changes in tag records to
                     the log file is turned off.
Voltage_control_mode The loadbox has three operation modes:
                     a constant current mode, a constant voltage
                     mode and a constant power mode. These two
                     commands are used to switch the loadbox
                     between these modes of operation.
Current_control_mode The loadbox has three operation modes: a
                     constant current mode, a constant voltage
                     mode and a constant power mode.
                     These two commands are used to switch
                     the loadbox between these modes of operation.

Table 9 describes a set of program flow commands that may be used to control the execution flow of a script.

TABLE 9
Program Flow Commands
Command	Parameters	Description
If	Tag, Condition	Allow a command or block to be
		executed only if the operational level of
		a tag (which may be a control or data tag)
		meets a condition
AndIf	Tag, Condition	Allows a second mandatory If
		condition to be added to an If command
OrIf	Tag, Condition	Allows an alternative If condition to
		be added to an If command
Wait_Until	Tag, Condition	Delays execution of the script
		until the operating level of a tag
		meets a condition
Delay	Time	Delays execution of the script for the
		specified time
Verify—		Insures the test is in good condition,
Safeties		and is ready to proceed to the next
		test stop.
Else		Allows a command or block to be
		defined for execution if the condition of
		an If command was not true.
EndIf		Ends a block of commands executed
		in response to an If command.

Table 10 defines a set of block commands that may be used to define a block of commands. A block of commands are executed as a whole in response to an If, Elself, Wait_Until or other program flow commands.

TABLE 10
Block Commands
Command	Parameters	Description
BeginBlock		Defines the beginning of a
		block of commands
EndBlock		Defines the end of a
		block of commands
ExitBlock		Used within a block of commands.
		Moves execution to the first
		instruction after the end of the block
Include	Filename	Causes the identified file to be read
		from a storage device and treated as if it was
		literally inserted in place of the command.

Table 11 defines a set of documentation commands that allows comments to be inserted into a script without affecting the execution of the script.

TABLE 11
Documentation Commands
Command	Parameters	Description
Rem		Placed at the beginning of
		a line in a script. It results in the entire
		line being ignored by the script
		compiler 404
;		Placed after another
		command in a line of a script. It causes
		the script compiler 404 to ignore the
		rest of the line, including the ;
		command itself.
Print	String	Causes the string to be displayed
		on an output device (such as a printer
		or display screen).
Write_comment	String	Causes the entire mapped file to be
		recorded in a log file and identified
		with the string.
Display	Tag#	Causes the operating level
		of the tag to be displayed.

As is well known, the script can be constructed using an automated program for making the script. A user can select a command and then the automated program will give a list of possible parameters and other information from which to choose. This helps to ensure that the command syntax is correct. Also, loops can be put in the script and can be repeat loops. Modification to the script can be made when the script is running, and there is no need to shut down or reload a script. When a sub-script is called, a new window will come up. When a test experiences alarm conditions, an alarm recovery script will automatically be activated.

Other variations and modifications of the invention are possible. All such modifications or variations are believed to be within the scope of the claims as appended hereto.

Claims

1. A system for testing a fuel cell, the system comprising: (a) testing means having a control device for controlling a controllable condition of the fuel cell; (b) a user interface for providing a script language comprising a control command type having an operating level field for receiving a selected operating level of the control device, wherein a test script is writeable using the script language such that the test script includes a control command of the control command type, the control command being derivable from the control command type by inserting the selected operating level of the control device into the operating level field of the control command; (c) a compiler for compiling the test script to provide a test program; and, (d) a system manager for controlling the control device according to the test program.

2. The system as defined in claim 1 wherein the compiler is operable to compile the test script to provide the test program by converting the selected operating level defined in the operating level field of the control command to a device operating level for controlling the control device to operate at the selected operating level.

3. The system as defined in claim 1 wherein the testing means comprises a plurality of control devices for controlling a plurality of controllable conditions of the fuel cell; the script language comprises a plurality of device identifiers for identifying the plurality of control devices, each control device in the plurality of control devices being identifiable by an associated device identifier in the plurality of device identifiers; the control command type comprises a device identification field for receiving the associated device identifier for a selected control device; and, the test script is writeable using the script language such that the test script includes a plurality of control commands of the control command type; and each control command in the test script includes, (i) in the operating level field of the control command, the selected operating level of the selected control device, and, (ii) in the device identification field, the associated device identifier for the selected control device.

4. The system as defined in claim 1 wherein the testing means comprises a plurality of control devices for controlling a plurality of controllable conditions of the fuel cell; the script language comprises a plurality of device identifiers for identifying the plurality of control devices, each control device in the plurality of control devices being identifiable by an associated device identifier in the plurality of device identifiers; the script language comprises a plurality of control command types, each control command type in the plurality of control command types having (i) an associated operating level field for receiving the selected operating level of a selected control device controlled by the control command, and (ii) a device identification field for receiving the associated identifier of the selected control device; and, the test script is writeable using the script language to include a plurality of control commands of the plurality of control command types such that each control command in the plurality of control commands defines, (i) in the operating level field of the control command, the selected operating level of the selected control device, and, (ii) in the device identification field, the associated device identifier for the selected control device.

5. The system as defined in claim 4 wherein the plurality of control devices comprises at least one flow controller for controlling at least one of an anode gas flow and a cathode gas flow; the plurality of control command types comprises a set_flow control command type, wherein the operating level field of the set_flow control command type is operable to receive a selected flow control level, and the device identification field of the set_flow control command type is operable to receive the associated device identifier of a selected flow controller in the at least one flow controller; and, the plurality of control commands includes a set_flow control command of the set_flow control command type.

6. The system as defined in claimed 5 wherein the script language further comprises a stoichiometric relational command type having a stoichiometry-defining field for receiving a selected stoichiometric ratio and a device identification field for receiving the associated device identifier for a selected flow controller; the test script is writeable using the script language such that the test script includes a stoichiometric relational command of the stoichiometric relational command type wherein the stoichiometric relational command is derivable from the stoichiometric relational command type by inserting (i) the selected stoichiometric ratio into the stoichiometry-defining field, and (ii) the associated device identifier for the selected flow controller into the device identification field; and, the system manager is operable to determine an associated flow control level for the selected flow controller based on at least one variable, the at least one variable including the selected stoichiometric ratio.

7. The system as defined in claimed 6 wherein the at least one variable further includes a load current of the fuel cell.

8. The system as defined in claim 4the plurality of control devices comprises at least one temperature controller; the plurality of control command types comprises a temperature control command type, wherein the operating level field of the temperature control command type is operable to receive a selected temperature control level, and the device identification field of the temperature control command type is operable to receive the associated device identifier of a selected temperature controller in the at least one temperature controller; and, the plurality of control commands includes a temperature control command of the temperature control command type.

9. The system as defined in claimed 4 wherein the plurality of control devices comprises at least one load controller for controlling a load on the fuel cell provided by a load box; the plurality of control command types comprises a load control command type, wherein the operating level field of the load control command type is operable to receive a selected load control level, and the device identification field of the load control command type is operable to receive the associated device identifier of a selected load controller of the at least one load controller; and, the plurality of control commands comprises a set_load control command for designating the load level.

10. The system as defined in claim 4the plurality of control devices comprises at least one pressure controller; the plurality of control command types comprises a set_pressure control command type, wherein the operating level field of the set_pressure control command type is operable to receive a selected pressure control level, and the device identification field of the set_pressure control command type is operable to receive the associated device identifier of a selected pressure controller in the at least one pressure controller; and, the plurality of control commands comprises a set_pressure control command of the set_pressure control command type.

11. The system as defined in claim 4 wherein at least one control command type in the plurality of control command types further comprises an associated ramp field for receiving a ramp rate for changing the operating level of the selected control device defined in the associated operating level field; the test script is writeable using the script language such that the plurality of control commands comprises a ramp control command defining the ramp rate for changing the operating level of the selected control device defined in the associated operating level field.

12. The system as defined in claim 4 wherein the compiler is operable to convert the test script to the test program by, for each control command in the plurality of control commands, converting the selected operating level defined in the operating level field of the control command to a device operating level for controlling the control device identified by the associated device identifier to operate at the operating level specified in the operating level field of the control command.

13. The system as defined in claim 4 further comprising a script editor for writing the test script using the script language.

14. The system as defined in claim 13 wherein, when a control command type is selected from the plurality of control command types, the script editor is operable to provide a plurality of possible parameters for defining a control command of the control command type.

15. The system as defined in claim 14 wherein the plurality of possible parameters comprises a range of possible operating levels, such that when the control command type is selected from the plurality of control command types, the script editor provides the range of possible operating levels for selection of the selected operating level to be inserted into the associated operating level field of the control command.

16. A method in a data processor for controlling a controllable condition of a fuel cell via a control device, the method comprising: (a) providing a script language comprising a control command type having an operating level field for receiving a selected operating level of the control device; (b) deriving a control command from the control command type by inserting the selected operating level of the control device into the operating level field of the control command; (c) writing a test script using the script language such that the test script includes the control command; (d) compiling the test script to provide a test program; and, (e) controlling the control device according to the test program.

17. The method as defined in claim 16 wherein step (d) comprises converting the selected operating level defined in the operating level field of the control command to a device operating level for controlling the control device to operate at the selected operating level.

18. The method as defined in claim 16 wherein a plurality of controllable conditions of the fuel cell are controlled via a plurality of control devices; the script language comprises a plurality of device identifiers for identifying the plurality of control devices, each control device in the plurality of control devices being identifiable by an associated device identifier in the plurality of device identifiers; the control command type comprises a device identification field for receiving the associated device identifier for a selected control device; and, step (b) further comprises inserting the associated device identifier for the selected control device in the device identification field to derive the control command from the control command type.

19. The method as defined in claim 16 wherein a plurality of controllable conditions of the fuel cell are controlled via a plurality of control devices; the script language comprises a plurality of device identifiers for identifying the plurality of control devices, each control device in the plurality of control devices being identifiable by an associated device identifier in the plurality of device identifiers; the script language comprises a plurality of control command types, each control command type in the plurality of control command types having (i) an associated operating level field for receiving the selected operating level of a selected control device controlled by the control command, and (ii) a device identification field for receiving the associated identifier of the selected control device; and, step (b) further comprises deriving a plurality of control commands from the plurality of control command types by, for each control command in the plurality of control commands, inserting the selected operating level of the selected control device in the operating level field of the control command; and, inserting the associated device identifier for the selected control device in the device identification field.

20. The method as defined in claim 19 wherein the plurality of control devices comprises at least one flow controller for controlling at least one of an anode gas flow and a cathode gas flow; the plurality of control command types comprises a set_flow control command type, wherein the operating level field of the set_flow control command type is operable to receive a selected flow control level, and the device identification field of the set_flow control command type is operable to receive the associated device identifier of a selected flow controller in the at least one flow controller; and, the plurality of control commands includes a set_flow control command of the set_flow control command type.

21. The method as defined in claimed 20 wherein the script language further comprises a stoichiometric relational command type having a stoichiometry-defining field for receiving a selected stoichiometric ratio and a device identification field for receiving the associated device identifier for a selected flow controller; the test script is writeable using the script language such that the test script includes a stoichiometric relational command of the stoichiometric relational command type wherein the stoichiometric relational command is derivable from the stoichiometric relational command type by inserting (i) the selected stoichiometric ratio into the stoichiometry-defining field, and (ii) the associated device identifier for the selected flow controller into the device identification field; and, the method further comprises determining an associated flow control level for the selected flow controller based on at least one variable, the at least one variable including the selected stoichiometric ratio.

22. The method as defined in claimed 21 wherein the at least one variable further includes a load current of the fuel cell.

23. The method as defined in claim 19the plurality of control devices comprises at least one temperature controller; the plurality of control command types comprises a temperature control command type, wherein the operating level field of the temperature control command type is operable to receive a selected temperature control level, and the device identification field of the temperature control command type is operable to receive the associated device identifier of a selected temperature controller in the at least one temperature controller; and, the plurality of control commands includes a temperature control command of the temperature control command type.

24. The method as defined in claimed 19 wherein the plurality of control devices comprises at least one load controller for controlling a load on the fuel cell provided by a load box; the plurality of control command types comprises a load control command type, wherein the operating level field of the load control command type is operable to receive a selected load control level, and the device identification field of the load control command type is operable to receive the associated device identifier of a selected load controller of the at least one load controller; and, the plurality of control commands comprises a set_load control command for designating the load level.

25. The method as defined in claim 19the plurality of control devices comprises at least one pressure controller; the plurality of control command types comprises a set_pressure control command type, wherein the operating level field of the set_pressure control command type is operable to receive a selected pressure control level, and the device identification field of the set_pressure control command type is operable to receive the associated device identifier of a selected pressure controller in the at least one pressure controller; and, the plurality of control commands comprises a set_pressure control command of the set_pressure control command type.

26. The method as defined in claim 19 wherein at least one control command type in the plurality of control command types further comprises an associated ramp field for receiving a ramp rate for changing the operating level of the selected control device defined in the associated operating level field; step (b) comprises deriving a ramp control command from the at least one control command type in the plurality of control command types by inserting the ramp rate for changing the operating level of the selected control device defined in the associated operating level field.

27. The method as defined in claim 27 wherein step (d) comprises converting the test script to the test program by, for each control command in the plurality of control commands, converting the selected operating level defined in the operating level field of the control command to a device operating level for controlling the control device identified by the associated device identifier to operate at the operating level specified in the operating level field of the control command.