Aspects of the present disclosure relate to a system configured to measure the temperature of multiple items using infrared sensors.
Measuring the temperature of a location can be useful for identifying diminished performance and for determining or predicting device failures. Electrical devices and components often get hot when performance has diminished, a failure has occurred, or a failure is imminent. Many devices and components are also rated for peak performance in certain temperature ranges and may have minimum and/or maximum operating temperatures. In these cases, the temperature of the devices should be monitored to ensure the safe and efficient operation of the components. It is with these and other issues in mind that various aspects of the present disclosure were developed.
According to one aspect, a thermal monitoring system includes a control node for receiving, storing, and outputting temperature measurements from a plurality of thermal sensor nodes. Each thermal sensor node includes an infrared sensor, an ambient temperature sensor, a LED, and a controller with a memory for storing temperature measurements and a connection to the control node. The control node connects to the thermal sensor nodes using a data bus constructed from RJ45 terminated Ethernet cables. At each thermal sensor node the Ethernet cable is split by a T-connection into two cables that carry the same signals or into and out of the sensor. The first cable connects to the thermal sensor node and the second cable goes on to the next thermal sensor node where the cable can be split again by another T-connection, providing what is essentially a single cable with branches that connect each thermal sensor node. The control node periodically receives temperature readings from the thermal sensor nodes and provides an output to a user.
Implementations of the present disclosure involve a thermal monitoring system that utilizes infrared sensors to monitor the temperature of electronic, mechanical or other devices and electrical interconnects or other interconnections operating at various locations. The thermal monitoring system includes a control node and thermal sensor nodes. The thermal sensor nodes use an infrared sensor to determine the temperature of a location. One advantage of the system is that the infrared sensor measures (detects) temperature remotely without physical contact. Thus, the system may be deployed in difficult to access areas, potentially dangerous areas (to the equipment), and areas where physical contact is challenging. In some arrangements, such as one employing a matrix of infra-red sensors, a single node may monitor several devices in a viewing area of interest. The thermal sensor nodes also determine ambient temperature at the location. In some arrangements, comparison of the viewed temperature and the ambient temperature may be used to detect a problem with the monitored device. Temperature readings may be stored locally at each thermal sensor node until the control node requests the temperature readings, or readings are transmitted. The control node then may provide an output of the temperature readings at each node and analyze the temperature data, among other functions.
Monitoring temperature at components such as at bearings, electrical connections, electrical devices, and computing components is especially important in certain applications. For example, properly functioning electrical interconnects are essential for reliable power distribution in data centers. Data centers include a large number of servers and various other computing components and associated infrastructure, requiring large amounts of power. As a result of the high power requirements, high voltage electrical lines are often directly fed to the data center. Transformers convert the high voltage to a suitable lower voltage for distribution in the data center. The transformers also provide power to uninterruptible power supplies (UPS) that, through the use batteries, provide backup power to the data center in the event of a power failure.
A data center power system, as well as many other power systems, have numerous electrical interconnects that undergo cycles of heating and cooling. The heating and cooling at an interconnect causes the parts and materials of the interconnect to expand, contract, and flex, causing the connections to loosen. The thermal monitoring system may determine whether a connection has become loose by measuring the temperature at the interconnection and identifying abnormally high heat generation, among numerous other uses.
Referring to
The control node 102 is a computing device configured to aggregate temperature information from the thermal sensor nodes 108-114 and provides output that is received by a server 150 that may be accessed using a personal computer 170, or other computing device, connected to the server 150 using a network 160. For example, the control node 102 may temporarily store the temperature information in a memory register, or some other form of memory, as the control node 102 receives information from each thermal sensor node 108-114. The control node 102 may then send the temperature information to the server 150 which updates a database 152 of temperature information. Once the temperature information has been sent to the server 150, the control node 102 may delete the temperature information from the memory and continue aggregating the temperature information from the thermal sensor nodes 108-114.
The control node 102 may store an identification of the node and a temperature reading for each of the thermal sensor nodes 108-114. The identification information may include a logical address for each thermal sensor node 108-114. In one example, the logical address may be assigned by the control node 102. The location information that identifies the physical location of the thermal sensor node and a description of what the thermal sensor node is monitoring may be included in the database 152. The location information is provided by a system user using the personal computer 170 that connects to the server 150 via a network 160. The location information may be inputted by the user utilizing a graphical user interface (GUI) 172 that is operating on the personal computer 170. In such an implementation, user editable fields are presented in the GUI whenever a node is added to the system. In some instances, the fields may be prepopulated with default values.
The control node 102 is configured to receive temperature information from each of the thermal sensor nodes 108-114. The information sent to the control node 102 may include the measured temperature at a location, a time stamp for the measurement, and the thermal sensor node's address. The control node 102 may retrieve the temperature information at regular intervals, upon a user command, or according to an alert generated by a thermal sensor node. For example, a user may program a temperature threshold at each thermal sensor node 108-114. In one example, the threshold in a user editable field is provided through the GUI. When a temperature measured by a thermal sensor node exceeds the threshold, the thermal sensor node may automatically send the temperature reading to the control node 102. In another example, the control node retrieves the temperature information and the temperatures are compared to a temperature threshold defined by a user or set as a default value. The comparison may occur at the control node or at the server. The control node 102 may automatically alert a user when a temperature exceeds a temperature threshold. For example, the control node 102 may generate alert that is received by the server 150. The server 150 may in turn generate and send an email to a user that includes the temperature and the physical location of the thermal sensor node that took the temperature. The server may also generate the alert.
In addition to providing a user with alerts regarding temperature anomalies, the control node 102 provides an output of the temperature information. In one example, the output may be sending a text file listing of all of the data collected by the control node 102 to the server 150. The server 150 may then parse the text file and update the database 152 with the new temperature information. A user may then access the database using the personal computer 170 and the GUI 172. The GUI 172 may then display the temperature information and corresponding location information in plain text or graphical form. Alerts may be displayed with any values exceeding a threshold.
The control node 102 may be also configured to processes the aggregated temperature information. The processing includes comparing the temperature information to one or more user designated temperature thresholds to determine if there is a hardware malfunction or failure at the location of the thermal sensor node. For example, the user may access the control node 102 via the network 160 and use the GUI 172 to designate that a component may not exceed an upper temperature threshold or fall below a lower temperature threshold. The control node 102 may compare measured temperatures to both upper and lower thresholds and/or compare the difference between the measured infrared temperature and the enclosure temperature. The control node 102 may then alert a user if a threshold is exceeded indicating a component that is malfunctioning or if a temperature is below a threshold, thus indicating that the component is not operating at all. In another example, the temperature thresholds set in the database 152. Thus, whenever new temperature data is provided by the control node 102 to the server 150, the server 150 may compare the temperatures to the appropriate thresholds.
Each of the thermal sensor nodes is connected to the control node 102 via the data bus 104, 106. In this example, the data buses 104, 106 are constructed using Ethernet patch cables 116-134 and T-Connectors 136-142. The Ethernet cables may include Category 5, Category 5e, or Category 6 cables terminated with RJ45 connectors, in specific possible implementations. The Ethernet cables include 8 individual wires that are used for both data communications and to provide power. Each thermal sensor node can connect a T-Connector 136-142 using a patch cable 118, 122, 128, 132, in one embodiment. Alternatively, the Ethernet cable may plug into the sensor and the signal feed out of an adjacent RJ45 connector. The T-Connectors 136-142 connect a single cable, for example patch cable 116, to two other cables, here cables 118, 120. The T-Connectors 136-142 extend the 8 wires of the incoming Ethernet cable 116 into two sets of 8 wires in the patch cable 118, which connects the thermal sensor node 110, and the patch cable 120, which connects the thermal sensor node 108 and any additional thermal sensor nodes. When the control node 102 sends a communication on the first branch 104 to the thermal sensor node 108, the communication travels down the first patch cable 116 to the first T-Connector 136. The T-Connector 136 connects the first patch cable 116 to the second patch cable 118 (and subsequently to the second thermal sensor node 110) and the third patch cable 120. The communication would then travel down the remainder of the patch cables (and thermal monitoring nodes) on the first branch 104. Each communication includes a logical address so that commands are only executed at their intended thermal sensor node. At the end of each scanning cycle a default logical address is sent to which newly connected sensors will reply to and subsequently be allocated an address by the controller. Alternatively, the signal may be transmitted through the first cable in the first RJ45 connector in the sensor and be continued from the second RJ45 connector in the sensor to an adjacent sensor.
As the data buses 104, 106 increase in length and/or the total number of thermal sensor nodes 108-114 increase, the data buses 104, 106 may not be able to provide sufficient power to additional thermal sensor nodes. Accordingly, Ethernet repeater 144 may be added to boost the signal strength and power along the data busses 106 to allow for additional expansion of the thermal monitoring system 100 to include the thermal sensor node 114.
Referring now to
The thermal sensor node 200 is configured to measure the temperature of a location and transmit temperature to the controller when prompted by the control node or according to a schedule. The temperature measured may include the temperature read by the infrared sensor 220, the temperature measured by the ambient temperature sensor 230, and/or the difference between the two temperatures. Each temperature reading may then be stored in a memory on the controller 210.
The controller 210 includes a processor 212, a BUS interface 214, a persistent memory 216, and any other circuitry necessary to operate the infrared and ambient temperature sensors 220, 230 and drive the LED(s) 240. The processor 212 receives input from the temperature sensors 220, 230 and performs any necessary calculations for resolving the output from the sensors. For example, if the temperature sensors provide an analog voltage indicating the temperature, the processor 212 may execute instructions for resolving the temperatures. The temperatures are then stored in the memory 216 along with other relevant information such as the time the measurement was taken. The processor 212 may also execute instructions to determine whether to activate one or more of the LEDs 240 according to the measured temperature. The sensor may also determine independently the viewed and ambient temperatures, and transmit them digitally to the processor.
The infrared sensor 220 measures infrared radiation corresponding to a temperature from some item of interest. The infrared sensor 220 is capable of measuring the temperature within a field of vision of the sensor. The field of vision is generally conical in shape starting at the infrared sensor 220 and expanding outward according to the infrared sensor's viewing angle. The further the infrared sensor 220 is from an item of interest, the larger the area that is in the infrared sensor's field of vision. Thus, if the infrared sensor 220 is positioned too far away from an item of interest, the sensor's field of vision may include items that are not of interest. Some infrared sensors are configured to output the average temperature measured within the sensor's field of vision. For example, if 75% of the infrared sensor 220's field of vision is 100 degrees Celsius, while the remaining 25% measures 30 degrees Celsius, then the infrared sensor 220 may provide an output indicating an average temperature of 82.5 degrees Celsius. Thus, if an infrared sensor is positioned so that the item of interest is not the only item within the infrared sensor's field of vision, the temperature measured by the infrared sensor 220 may not be accurate.
In addition to the infrared sensor 220, the thermal sensor node also includes the ambient temperature sensor 230 for providing the ambient temperature of the vicinity of the item of interest. Generally speaking, ambient temperature may be used for comparison to a measured item temperature to identify differences between the measured temperature and the temperature of the environment. The ambient temperature sensor 230 may include any temperature sensor that measures ambient temperature and produces an analog or digital output to the controller 210. For example, the ambient temperature sensor 230 may include a temperature sensitive diode that has with a voltage drop that varies according to temperature. In this case, the ambient temperature sensor 230 may provide the controller 210 with an analog voltage. The controller 210 may then perform arithmetic or use a lookup table to determine the temperature based on an analog voltage provided by the ambient temperature sensor 230. In another example, the ambient temperature sensor 230 may include a digital thermometer that produces a digital signal indicating the temperature.
In one example, the thermal sensor node 200 may be configured to drive one or more of the LEDs 240 to provide a visual indication of a temperature, and particularly if temperature is within threshold or out of threshold. The controller 210 may regularly receive a temperature measurement from the infrared sensor 220 and drive the LED(s) 240 according to the measured temperature. In another example, the controller may drive the LED(s) 240 according to the temperature differential between the ambient temperature and the temperature measured by the infrared sensor 220. For example, the controller 210 may activate the LED(s) 240 when the temperature difference exceeds a threshold. In another example, the LED(s) 240 may include a multi-color LED, such as a tri-color LED. Each of the colors of the LED may represent a different temperature status. For example, when the temperature difference is less than 20 degrees Celsius, the tri-color LED may output blue light, when the temperature difference is between 20 and 30 degrees Celsius, the tri-color LED outputs green light, and when the temperature difference exceeds 30 degrees Celsius, then the tri-color LED outputs red light. Similarly, if an indicator LED has more (or less) color outputs, more (or less) temperature ranges may be used to trigger a different color.
The temperature measured by the infrared sensor may be compared to the temperature measured by the ambient sensor to detect unusually hot components. For example, in a data center environment and particular in a set of batteries forming part of a UPS system, the infrared sensors may be positioned to detect temperatures of terminal connectors thereby identifying a loose connection which may become unusually hot. In such a situation, the thresholds may be set to consider the ambient temperature as well as the actual measured temperature to detect components that are not only unusually hot but also unusually hot relative to the surrounding temperature. Hence, the system may be programmed to look for measured temperature above a threshold, and/or measured temperature above ambient temperature, at a percentage of ambient (e.g., 120%) or otherwise. For example, if the ambient temperature is 120 F and the measured temperature is 125 F, the difference is only 5 degrees Fahrenheit. While the measured temperature may be hot for the device, it may not be unusually hot given the relatively hot ambient temperature. In another example, the IR sensor may be positioned to monitor a shipping joint carrying high current from or to a UPS. Flexing of the joint, like other similar type joints, due to expansion and contraction often causes such joints to loosen and thereby become warm relative to the surrounding ambient temperature thereby being monitorable by the system described herein.
The LED(s) 240 may also be used to aid in the placement of the thermal sensor node 200. For example, the LED 240 may be positioned such that the field of vision of the light emitted by the LED 240 is about the same as the field of vision of the infrared sensor 220. Thus, if the light emitted by the LED 240 is projected on a location, the projected light is roughly the same area that will be measured by the infrared sensor 220. The controller 210 may be configured so that the LED 240 is activated upon a user command provided to the command node and relayed to the thermal sensor node 200 so that the thermal sensor node 200 may be properly placed and positioned to measure the temperature of only the item of interest and not the temperature from other adjacent sources. In another example the LED or LEDs may be of a laser type and may be positioned to follow the infrared sensing area to give a visual display for correct placement.
The memory 216 may include both volatile and nonvolatile memory 218 for storing the temperature readings as well as the logical address of the thermal sensor node 200. The logical address of the thermal sensor node 200 is stored in the nonvolatile memory 218 and may be initially set at a default value. When the thermal sensor node is connected to the control node for the first time, the control node may recognize the new node based on the default address and assign the thermal sensor node 200 a new address that is unique to the thermal sensor node 200.
By default, each thermal sensor node 200 may be preprogrammed with a default address. The control node may be configured to automatically send a signal addressed to a node with the default address each time the control nodes retrieves temperatures from the thermal sensor nodes. For example, in a system with one thermal sensor node and it has an address of 1, each time the control node retrieves a temperature from thermal sensor node 1, and the control node may follow up with a message to a node with the address of 0. If a new thermal sensor node is connected, the new thermal sensor node will respond to the message. When the new thermal sensor node responds with the control node's message, the control node will send the new thermal sensor node a command assigning the new thermal sensor node 200 an available logical address (e.g., 2). The control node then retrieves a temperature from the new thermal sensor node and after receiving the temperature again sends out another query to nodes with an address of 0. Thus, new thermal sensor nodes may be dynamically added to the system by simply plugging a new thermal sensor node into the data bus. The user may later provide location information or any other information that defines the thermal sensor node.
The bus interface 214 is configured to receive power from the data bus 250 and to send and receive communications to and from a control node. Commands from the control node are received at the bus interface 214 and relayed to the processor 212. The processor 212 first compares the destination address of any commands with the logical address 218 of the thermal sensor node 200 prior to execution. For example, the thermal sensor node may receive a request for all of the temperature information that the node has stored and to delete the temperature information after sending. The bus interface 214 receives the command and relays the command to the processor. The process checks to see that the command is addressed to the node, sends the requested information to the control node using the bus interface 214 and data bus 250, and deletes the temperature information from the memory 216.
Referring now to
The horizontal positioning of the thermal sensor node 300 may be adjusted along the mounting bar 350. The direction of the thermal sensor node 300 may also be adjusted around the radius of the mounting bar 350. As described above, the infrared sensor 330 has a limited field of view, here denoted as the viewing angle Θ. As also described above, the infrared sensor 330 may be configured to measure an average temperature for the sensor's complete field of view. Thus, to most accurately measure the temperature at the interconnect 360, the thermal sensor node 300 may be adjusted so the infrared sensor 320 is aimed such that the field of view is primarily occupied by the device that the user wishes to measure (here interconnect 360). The mount 340 secures the thermal sensor node 300 to the mounting bar 350 once the desired placement of the thermal sensor node has been identified. The mount 340 may include a clamping mechanism that is flexible enough to allow the mount to expand enough to fit around the mounting bar 350 when force is applied, but rigid enough to clamp around the mounting bar, thus securing the mount 340 and thermal sensor node 300 in place. The mount may be an over counter clamp, zip tie, or any other suitable structure. In another embodiment, the mount 340 may include an appropriate fastener for securing the mount 340 to the mounting bar 350. For example, clamps, screws, bolts, or other fasteners may be utilized.
Referring to
The system bus 590 may be any of several types of bus structures including a memory bus or memory controller, a peripheral bus, a switched fabric, point-to-point connections, and a local bus using any of a variety of bus architectures. The system memory may also be referred to as simply the memory, and includes read only memory (ROM) 570 and random access memory (RAM) 580. A basic input/output system (BIOS) 572, containing the basic routines that help to transfer information between elements within the general purpose computer 500 such as during start-up, is stored in ROM 570. The general purpose computer 500 may further include a hard disk drive 520 for reading from and writing to a persistent memory and an optical disk drive 530 for reading from or writing to a removable optical disk such as a CD ROM, DVD, or other optical media.
The hard disk drive 520 and optical disk drive 530 are connected to the system bus 590. The drives and their associated computer-readable media provide nonvolatile storage of computer-readable instructions, data structures, program engines and other data for the general purpose computer 500. It should be appreciated by those skilled in the art that any type of computer-readable media which can store data that is accessible by a computer, such as magnetic cassettes, flash memory cards, digital video disks, random access memories (RAMs), read only memories (ROMs), and the like, may be used in the example operating environment.
A number of program engines may be stored on the hard disk, optical disk, ROM 570, or RAM 580, including an operating system 582, a thermal monitoring application 584, and one or more application programs 586. A user may enter commands and information into the general purpose computer 500 through input devices such as a keyboard and pointing device connected to the USB or Serial Port 540. These and other input devices are often connected to the processor 510 through the USB or serial port interface 540 that is coupled to the system bus 590, but may be connected by other interfaces, such as a parallel port. A monitor or other type of display device may also be connected to the system bus 590 via an interface, such as a video adapter 560. In addition to the monitor, computers typically include other peripheral output devices (not shown), such as speakers and printers.
The general purpose computer 500 may operate in a networked environment using logical connections to one or more remote computers. These logical connections are achieved by a network interface 550 coupled to or a part of the general purpose computer 500; the invention is not limited to a particular type of communications device. The remote computer may be another microcontroller-based computing device, such as a thermal sensor node or a computer, a server, a router, a network PC, a client, a peer device, or other common network node, and typically includes many or all of the elements described above relative to the general purpose computer 500. The logical connections include a local-area network (LAN) a wide-area network (WAN), or any other network. Such networking environments are commonplace in office networks, enterprise-wide computer networks, intranets and the Internet, which are all types of networks.
The network adapter 550, which may be internal or external, is connected to the system bus 590. In a networked environment, programs depicted relative to the general purpose computer 500, or portions thereof, may be stored in the remote memory storage device. It is appreciated that the network connections shown are example and other means of and communications devices for establishing a communications link between the computers may be used.
The embodiments of the invention described herein are implemented as logical steps in one or more computer systems. The logical operations of the present invention are implemented (1) as a sequence of processor-implemented steps executing in one or more computer systems and (2) as interconnected machine or circuit engines within one or more computer systems. The implementation is a matter of choice, dependent on the performance requirements of the computer system implementing the invention. Accordingly, the logical operations making up the embodiments of the invention described herein are referred to variously as operations, steps, objects, or engines. Furthermore, it should be understood that logical operations may be performed in any order, unless explicitly claimed otherwise or a specific order is inherently necessitated by the claim language.
The foregoing merely illustrates the principles of the invention. Various modifications and alterations to the described embodiments will be apparent to those skilled in the art in view of the teachings herein. It will thus be appreciated that those skilled in the art will be able to devise numerous systems, arrangements and methods which, although not explicitly shown or described herein, embody the principles of the invention and are thus within the spirit and scope of the present invention. From the above description and drawings, it will be understood by those of ordinary skill in the art that the particular embodiments shown and described are for purposes of illustrations only and are not intended to limit the scope of the present invention. References to details of particular embodiments are not intended to limit the scope of the invention.
This application claims priority under 35 U.S.C. §119 from U.S. provisional application No. 61/904,628 entitled “SYSTEM AND METHOD FOR DISTRIBUTED THERMAL MONITORING,” filed on Nov. 15, 2013, the entire contents of which are fully incorporated by reference herein for all purposes.
Number | Date | Country | |
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61904628 | Nov 2013 | US |