The present disclosure relates generally to a warning system, and particularly to the monitor and control of the warning system.
Various types of active warning devices are installed at railroad-highway grade crossings to warn motorists of an approaching train. Typical active warning devices include bells, flashing lights (singular or plural), and gates, for example. Locally isolated warning systems require local inspection to ensure proper operation and maintenance, which is time intensive and costly. Specific aspects of a flashing light warning system that must be periodically inspected include light intensity presented to the motorist, flash period of the flashing light, and proper alignment of the flashing light with the roadway approach. An alternative to the locally isolated warning system is a centrally controlled warning system, which includes a central controller that receives, processes, and responds to sensor data. Centrally controlled warning systems are costly to install and do not provide local intelligence at the sight of the warning system.
In one embodiment, a system for monitoring and controlling activation of a warning system includes a sensor module locally coupled to the warning system for sensing and controlling a flashing light of the warning system, a transceiver responsive to a microcontroller, and a power line interface for interfacing between the transceiver and the power line servicing the warning system. The sensor module includes a sensor arranged for sensing the flashing light, the microcontroller coupled to the sensor, and a power supply for providing power to the sensor module.
In another embodiment, a method for monitoring and controlling a warning system includes receiving power from a power supply, receiving a sensor input at a microcontroller, processing the sensor input at the microcontroller, communicating the sensor input to an equipment bungalow via a power line interface, and recording the sensor data from the sensor input at a data recorder.
In a further embodiment, a method for estimating the light intensity of a flashing light at a warning system includes processing a sensor signal to identify flash intensity during “ON” and “OFF” portions of a flashing light cycle, comparing light intensity values between the “ON” and “OFF” portions of the flashing light cycle, and determining lamp “ON” intensity above ambient light.
In another embodiment, a system for monitoring and controlling a warning system includes a power supply means for providing power to monitor and control the warning system, a control means for controlling the warning system, a monitoring and recording means for monitoring the warning system and recording information relating thereto, a mounting means for mounting a sensor to the warning system, a communication means for communication sensed information relating to the warning system to maintenance personnel, a detection means for detecting performance degradation of the warning system, a status detection means for detecting the status of the warning system, a warning means for detecting abnormal conditions at the warning system, a detection means for detecting negative influences from environmental effects at the warning system, and a communication means for accessing operating standards stored at a data recorder.
Referring to the exemplary drawings wherein like elements are numbered alike in the accompanying Figures:
An embodiment of the present invention provides an apparatus and method for monitoring and controlling activation of a visual warning system, such as a flashing light warning system, at a railroad crossing that may also include crossing gates. While the embodiment described herein depicts a flashing light system as an exemplary warning system, it will be appreciated that the disclosed invention is also applicable to other warning systems, such as traffic light, fire alarm, noxious fume alarm, or over temperature alarm warning systems for example. The exemplary embodiment monitors the remote crossing warning systems from a central location, using sensors to determine status and performance of warning devices and compliance with predetermined operating points, thereby performing central monitoring of the remote (locally isolated) warning systems rather than central controlling of the remote warning systems.
In a typical crossing configuration there is no local power supply, rather there are one or more low voltage power supplies, which are derived from 60 Hertz utility power that is stepped down from 110 Volts to 10 Volts and used to charge one or more batteries. One of the batteries is typically used to power a train detection circuitry and a flashing light controller, and a second battery is typically used for powering the crossing lights, bells, and gate for example. The number of low voltage batteries may vary according to a specific application. When an approaching train is detected, equipment in bungalow 240 triggers the alternate flashing of the lamps 130, which includes the opening and closing of the power circuit to the lamps 130. Thus, half of the lamps 130 flash “ON” when the other half flash “OFF”, and vice versa. In an embodiment of the invention, parasitic capacitor power supply 170 allows sensor module 120 to operate continuously throughout the flash “ON” and “OFF” sequence, thereby enabling sensing of both “ON” and “OFF” lamp intensities. In this arrangement, local power supplies are not required in the lamp head 270 to power the lamp 130 and the sensor 140. Also not required are additional timing signals to determine a lamp “ON” condition.
System 100 also includes a transceiver module 180 having a transceiver 190 and a power line interface 200. Transceiver 190 communicates with microcontroller 160 and power line interface 200. Power line interface 200 interfaces between transceiver 190 and the power line 210 servicing flashing light system 110. Power line interface 200 affords a band pass filter response which attenuates the AC or DC flashing light power signal while enabling the chosen power line communication frequency carrier signal to pass without attenuation. A frequency on the order of about 50 kHz or about 100 kHz may be utilized as power line carrier signal. In an alternative embodiment, transceiver module 180 is integrated with sensor module 120.
Referring now to
Sensor hub 250, which includes one transceiver 190 for each flashing light circuit of flashing light system 110, operates as a combiner for multiple power line circuits and interacts with those multiple power line circuits via power line interface 200. A crossing typically has two masts, each mast having four lights. Half of the lights on a given mast flash “ON” while the other half are “OFF”. Thus, there are two flashing light circuits per mast. A crossing may have multiple masts as well as overhead cantilever structures with additional flashing lights. To avoid a short circuit between power supplies during power line communications, each flashing light circuit has a separate transceiver, which demodulates data bits off its respective power line communications circuit and forwards the resulting signal to another microcontroller or to a shared memory. In this manner, sensor hub 250 acts like an active multiplexer.
In another embodiment, sensor module 120 incorporates other sensors 150 for monitoring all four lights on a mast. In such a configuration, only one power line circuit of the two supplying the mast is used for exchanging sensor data with sensor module 120.
The location of sensor 140 on flashing light system 110 for monitoring lamp 130 is best seen by now referring now to
In the exemplary embodiment depicted in
The exemplary photosensor 140 is responsive to irradiance and provides an indirect measurement of the intensity presented by lamp 130. The photo current generated by the photosensor 140 is linearly dependent upon the incident irradiance over a nominal range of irradiance.
Radiometry is the study of optical radiation. Photometry deals with the visual response of a human to light. As such, radiometry measurements are concerned with total energy content of radiation while photometry focuses on that portion of the radiant energy that humans can see. Radiometric power is expressed as radiant flux, while luminous flux serves to quantify the power of visible light. Irradiance is a measurement of radiometric flux per unit area, or flux density. Illuminance is a measure of visible flux density. Radiant Intensity is a measure of radiometric power per unit solid angle, expressed in watts per steradian. Similarly, luminous intensity is a measure of visible power per solid angle, expressed in candela (lumens per steradian). Intensity is related to irradiance by the inverse square law, shown below in an alternate form: I=E*d2.
As discussed above, system 100 includes parasitic power supply (PPS) 170, which is best seen by now referring to
Switch 460 is located along with local crossing lamp power supply 135 in equipment bungalow 240. Upon detection of an approaching train and activation of the crossing warning devices, switch 460 is alternately opened and closed to connect power supply 135 with lamp 130 to light the lamp. Local crossing power supply 135 may be either ac power supply or dc power. When switch 460 is closed, power supply 135 provides power to sensor module 120 and to energy storage circuit 430 when flashing light 130 is ON. When flashing light 130 is OFF, energy storage circuit 430 provides power to sensor module 120 via out 450 and voltage input 125. Energy storage circuit 430 includes a capacitor 490 having a capacitance sized for a specified flash rate. In an embodiment, capacitor 490 has a capacitance of 37.6 micro farads (mF) for a flash rate of 35 flashes-per-minute.
The voltage supplied by power supply 135 and applied across lamp 130 is typically between about 9.5 and about 12 volts ac or dc. The voltage output (at 450, shown with dummy resistor 470 in
Microcontroller 160 is configured with embedded functions for receiving and managing inputs from a plurality of sensors 140, 150. In an embodiment, microcontroller 160 senses light intensity when flashing light 130 is both ON and OFF by receiving a first light intensity signal from sensor 140 when flashing light 130 is ON and a second light intensity signal from sensor 140 when flashing light 130 is OFF, which microcontroller 160 uses to eliminate the ambient light bias intensity from the flashing light intensity. The adjusted flashing light intensity may then be recorded at data recorder 260.
In an embodiment, microcontroller 160 is configured with embedded functions for communicating with transceiver 190, thereby enabling communication with data recorder 260 in equipment bungalow 240. Data recorder 260 not only records data received from microcontroller 160 but also stores predefined nominal operating characteristics (such as flash rate for example), threshold values (such as minimum and maximum lamp intensities), and the logical addresses for multiple lamps 130 being serviced by lamp sets 220, 230. The communication links between sensors 140, 150, microcontroller 160, and data recorder 260, enables microcontroller 160 to analyze the inputs from a plurality of sensors 140, 150 for comparison against the stored nominal operating characteristics and threshold values. In another embodiment, microcontroller 160 is configured with embedded functions for locally testing flashing light system 110 against nominal operating characteristics, the test results being communicated across power line interface 200 to data recorder 260 in equipment bungalow 240. If an abnormal operating condition is detected, microcontroller 160 sends an abnormal condition signal across power lines 210, via power line interface 200, equipment bungalow 240 and wide area network 245, to a monitoring station 105 for corrective action (see
Referring now to the process 800 of
A subroutine (process) 860 for estimating the flash intensity of flashing light 130 is depicted in
In general,
Referring now to
At step 870, an exponentially weighted filter is applied to the sensor data sample with low pass frequency characteristic of 2 Hz stated above. A value En is calculated according to the equation:
En=k*(In−En−1)+En−1. Equa. 4
Where subscripts “n” and “n−1” refer to the current and previous data points, respectively. Next, it is determined 872 if the filtered data value En is greater than the maximum value (MAX). If step 872 is true, then MAX is set 874 equal to En and the flash intensity is set 876 equal to the difference between MAX and MIN.
If step 872 is false, then it is determined 878 if En is less than MIN. If step 878 is true, then MIN is set 880 equal to En and the flash intensity is set 876 equal to the difference between MAX and MIN.
If step 878 is false, then it is determined 882 if En is within +/−20% of the sum of MAX plus MIN divided by two. If step 882 is true, then CZ is set 884 equal to (MAX+MIN)/2.
If step 882 is false, then subroutine 860 is returned 886 to the main program with no change in the flash intensity.
After steps 876 and 884, subroutine 860 is transfers 886 to routine “A” with the respective update values.
The CZ crossing point is calculated if average value (EMA) is within 20% of (max+min)/2. This ensures the CZ validity against data fluctuations.
At the entry of routine “A” 886, it is determined 950 whether En is greater than CZ. If 950 is true, then at 952 the ON-samples are counted and the ON-flashes are counted. Since the sampling rate may be different from the flashing rate, both counts are registered. If 950 is false, then at 954 the OFF-samples and OFF-flashes are counted. At 956 it is determined whether an ON condition exists. If 956 is true, then the Flash Rate is calculated according to the equation in block 958. If 956 is false, then program logic passes to path “B” 960 and the program logic enters block 869. After block 958, Flash Parameter Registers are updated at 962, a Good Data Flag is set at 964, and the Flash Parameters are reported at 966 to Sensor Hub 250. In general, routine “A” calculates a valid Flash rate and increments the appropriate logic counter registers.
By employing a controller area network (CAN) link layer protocol within microcontroller 160, which is implemented in hardware in many purchasable microcontrollers (such as PIC18C658 device from Microchip for example), and an ON/OFF signaling scheme (supported by CAN) with a modulated carrier frequency as a physical layer, data can be communicated across power line 210 via transceiver module 180.
Referring now to
Control means 905 is provided by microcontroller 160, which interacts between sensors 140, 150 and transceiver 190 to control the information flow through power line interface 200 to power line 210 and equipment bungalow 240. Power to microcontroller 160 is provided by power line 210 and power supply 170, as discussed above. Monitoring and recording means 910 is provided by data recorder 260 in equipment bungalow 240, which is accessible through microcontroller 160. The means of mounting 915 sensors 140, 150 on flashing light system 110 is provided by known methods such as screws, bolts, brackets, welding, for example. An embodiment of sensor 140 mounted on flashing light system 110 is depicted in
In a further embodiment depicted in
While the invention has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims. Moreover, the use of the terms first, second, etc. do not denote any order or importance, but rather the terms first, second, etc. are used to distinguish one element from another.
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Number | Date | Country | |
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20040119587 A1 | Jun 2004 | US |