Abstract:
Trainline controller including testing of signal quality on a trainline network by commanding each node to transmitter calibration signal. A signal detector is connected to the trainline at a common junction with a head end termination circuit. A stuck-on transmitter is determined by a transmission current drawn by the transceiver is on for a present amount of time.

Description:
BACKGROUND AND SUMMARY OF THE INVENTION  
         [0001]    The present invention relates to electropneumatic brake control on a train and more specifically to the electronic portion of the trainline controller.  
           [0002]    Electropneumatic brake control valves are well known in the passenger railroad art and the mass transit railroad art. Because the trains are short and are not involved generally in a mix and match at an interchange of different equipment, the ability to provide pneumatic and electrical control throughout the train has been readily available in the passenger and the mass transit systems. In freight trains, the trains may involve as much as 100 cars stretching over one mile or more. The individual cars may lay idle in harsh environments for up to a year without use. Also, because of the long distance they travel, the cars are continuously moved from one consist to another as it travels to its destination. Thus, the use of electropneumatic-pneumatic valves in the freight trains has been very limited.  
           [0003]    A prior art system with electropneumatic train brake controls is illustrated in FIG. 1. An operator control stand  10  generally has a pair of handles to control the train braking. It controls a brake pipe controller  12  which controls the brake pipe  14  running throughout the train. It also includes a trainline controller  16  with power source  17  which controls the trainline  18  which is a power line as well as an electrical communication line. The control stand  10 , the brake pipe controller  12  and the trainline controller  16  are located in the locomotive.  
           [0004]    Each car includes a car control device  20  having a car ID module  22  and a sensor  24  connected to the trainline  18 . The pneumatic portion of the car brakes include a brake cylinder  26 , a reservoir  28  and a vent valve  29 . The car control device  20  is also connected to the brake pipe  14  and the trainline  18 . The brake pipe controller  12  is available from New York Air Brake Corporation as CCBII® and described in U.S. Pat. No. 6,098,006 to Sherwood et al. The trainline controller  16  and the CCD  20  are also available from New York Air Brake as a product known as EP60®. The car control device  20  is described in U.S. Pat. No. 5,967,620 to Truglio et al and U.S. Pat. No. 6,049,296 to Lumbis et al. Each of these patents and products are incorporated herein as necessary for the understanding of the present patent.  
           [0005]    The trainline controller  16  is shown in detail in FIG. 2. The control stand  10  includes EP brake controller  30  and an operator interface unit or display  31  which are connected to a trainline communication controller  40 . The trainline communication controller  40  is connected to the trainline  18  and receives 75 volts DC from the locomotive battery. It is also connected to the locomotive systems  32 . The locomotive control  16  also includes a trainline power controller  50  connected to the trainline  18 . It is also connected to 75 volts DC from the locomotive as well as the trainline power supply  38 . The trainline power supply  38  provides all of the voltage necessary for operation of the electronics of the trainline power controller as well as the trainline  18 . The 230 volts are applied to the trainline  18  in the normal operational mode. The 24 volts are the volts that is applied to the trainline  18  during synchronization.  
           [0006]    The example illustrated in FIG. 2 is for a lead locomotive and a trailing locomotive. The trainlines between the locomotives are connected by EP trainline connectors  34 . The leading EP line connector  34  has a head end termination HETT  36  terminating the trainline. The trainline communications controller  40  controls the trainline and communication and the power through the trainline power controller  50 . Although the trainline power controller  50  and the trainline power supply  30  are shown in a second locomotive, they may also be located in the leading locomotive. Also, it is anticipated that all of the locomotives will have a trainline communication controller and a trainline power line controller therein. Using multiple power sources to power the trainline is described in U.S. Pat. No. 5,907,193 to Lumbis. Testing the trainline before powering up is also described in U.S. Pat. No. 5,673,876 to Lumbis et al.  
           [0007]    The present invention is improvements in the trainline controller electronics. It includes a method for testing a signal quality for each node in the wire network on the train. This method includes commanding each node to be in a receiving node followed by commanding each node, one at a time, to transmit a calibration signal. Then, a determination is made of the quality of the calibration signals as function of the length of the transmission path on the wire. A system to perform this method includes a transceiver and a level sensor circuit connected to the trainline. A controller connected to the transceiver and level sensor controls the sending of the commands by the transceiver to each node and receives signals from the level sensor circuit. The transceiver and level sensor circuits are connected to the trainline by a common transformer. The level sensor circuit includes a filter and signal conditioning circuits. The filter may have a variable gain set by the controller. The signal conditioning circuit may include a rectifier and peak detector. It may also includes an analog to digital converter connecting the peak detector to the controller. The level sensor circuit may include a sensor control to store the signals from the signal conditioning circuit and send it to the controller. The sensor control may signal the controller that a conditioned calibration signal is ready and the controller requests transmission of the condition calibration signal. The sensor control may detect the presence of the calibration signal and activates the signal conditioning circuit.  
           [0008]    The trainline communication controller on a locomotive and a wired network with the nodes in the car may include a transceiver and a signal detector connected to the trainline. A head end termination circuit is connected to the trainline at a common node with the signal detector. The controller is connected to the transceiver and the signal detector. This signal detector may include a transceiver connected to the trainline which detects the presence of a transmission packet. A multiplexer may be included which connects the signal detector to a front end and a rear end termination circuits. The detector may be connected to the junction by inductors and a rectifying bridge.  
           [0009]    A method is provided for identifying stuck-on transmitting of a transceiver in a train network where the transceiver draws a first current for transmitting and a second car for receiving. The method includes sensing the current drawn by the transceiver and determine if the sensor current is between the first and second currents. Finally, a stuck-on detector is identified if the sensed current is determined to be between the first and second currents for more than a preset amount of time. The current can be sensed using a current mirror and the determining is performed by a comparator connected to the current. The identifying can be performed by a microprocessor which measures the time and identifies the stuck-on transmitter. The microprocessor may also disable a transmitter when identified is stucked on.  
           [0010]    A transceiver control circuit may also be provided to perform the method and would include a current sensor, a comparator, and a timer. A controller identifies a stuck-on transmitter when the amount of time, the sensor current is determined to be between the first and second currents, is more than a preset amount of time. The current sensor includes a current mirror contact connected to the receiver and comparator. Also, the timer and the controller may be in a microprocessor. The controller disables a transmitter when identified as stuck-on. This is performed by providing a disable signal at the reset terminal of the transceiver. A reset circuit is connected to the reset terminal of the transceiver and the controller.  
           [0011]    Other objects, aspects and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]    [0012]FIG. 1 is an electropneumatic brake control system of the prior art.  
         [0013]    [0013]FIG. 2 is a block diagram of the trainline controller of the prior art.  
         [0014]    [0014]FIG. 3 is a block diagram of the trainline communications controller of the trainline controller of the present invention.  
         [0015]    [0015]FIG. 4 is a block diagram of the power supply system of the trainline communications controller according to the principles of the present invention.  
         [0016]    [0016]FIG. 5 is a block diagram of the I/O interface of the trainline communications controller according to the principles of the present invention.  
         [0017]    [0017]FIG. 6 is a block diagram of the network interface of the trainline communications controller according to the principles of the present  
         [0018]    [0018]FIG. 7 is a block diagram of the trainline communication signal detector circuit according to the principles of the present invention.  
         [0019]    [0019]FIG. 8 is a block diagram of the suck-on transceiver circuit according to the principles of the present invention. invention.  
         [0020]    [0020]FIG. 9 is a block diagram of the calibration level sensing circuit according to the principles of the present invention.  
         [0021]    [0021]FIG. 10 is a block diagram of the trainline power controller according to the principles of the present invention.  
         [0022]    [0022]FIG. 11 is a block diagram of another embodiment of the trainline communication signal detector circuit according to the principles of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0023]    As shown in FIG. 3, the trainline communication controller  40  includes a power supply system  402 , an I/O interface  40 , a network interface  406  and a single board computer and interface  408 . The power supply system  402  is connected to the battery and receives voltage from it and provides the necessary voltage for the circuit in the trainline controller  40 . Output voltage V 24  is provided to the I/O interface  404 . The I/O interface is connected to the network interface  406  by DC NETA and DC NETB. These are Lonwork networks. I/O interface  404  is also connected to the SBC interface by a RS232 line. The network interface  406  is connected to the SBC and interface by Lon net DC NETA and DC NETB. I/O interface  404  converts the V 24  into V 5  and provides it to the network interface  406  and the SBC and interface  408 .  
         [0024]    The I/O interface  404  provides the interface between the Lonworks direct connect network DC NETA and the locomotive. The I/O interface  404  is connected outside the trainline communication controller  40  by analog inputs AD, digital inputs DD, RS 232 communication isolated port, two RS422 isolated ports and relay outputs. The RS422 ports may be connected to distributive power systems or an event recorder. The RS 232 port may be connected to a portable test unit.  
         [0025]    The network interface  406  provides an interface between an internal direct contact network and the external Lon network. The network interface  406  is connected to the trainline terminals TL, head end termination HETT of the forward and rear terminations and Lon networks FTTA and FTTB. The head end termination terminals HETT are connected to head end termination  36  at the forward end as well as one at the rear end of the locomotive.  
         [0026]    SBC and interface  408  includes a high performance single board computer SBC integrated with a custom design network adaptor. This assembly provides the direct communication between the SBC and the internal Lon network DC NETA and B. The connections outside the trainline communication controller for the single board computer are comm 2 ports and ethernet ports. Most of the output connections are to the locomotive systems  32 .  
         [0027]    It should be noted that Lonworks is the network choice of the industry, although other networks may be used. The basic nodes include neuron chips which communicate with each other as well as local transceivers and power line transceivers.  
         [0028]    The power supply system  402 , as illustrated in FIG. 4, connects the locomotive battery at terminals BTTY+ and BTTY− through filter  410  to a power supply  411 . The power supply may be, for example, an Melcher supply. It provides outputs V 24  and V 230 . Also connected to the output of the filter  410  is a low voltage inhibits circuit  412 . This monitors the voltage at the output of the filter which represents voltage of the battery. If the battery voltage is below a desired point, it produces a power supply inhibit signal to disable the power supply  411 . This will shut down the trainline communication controller  40 .  
         [0029]    The I/O interface  404  is shown in detail in FIG. 5. A voltage regulator  420  receives the V 24  from the power supply system  402  and provides voltages V 5  to the network interface  406  and the SBC and interface  408 . It also lights a diode  421  indicating that it is receiving power from the power supply system  402 . The RS 232 communication port from the SBC interface  408  goes through the level shifter  422 , optical isolator  423  and level shifter  424  to provide an isolated RS 232 port. An isolated DC to DC converter  425  powers the opto-isolator  423 . The HDLC or RS 422 port also goes through level shifter  426  opto-isolator  427 , having an isolator DC to DC converter  428  to a communication processor  429 . The communication processor  429  provides data to and from the memory system  430 .  
         [0030]    The controller of the I/O  432  is a neuron chip connected by a direct connect transceiver  433  to a direct connect network having an output DC NETA and DC NETB to the network interface  406 . The controller  432  includes additional memory  434 . The controller  432  is also connected to a SPI bus  436 .  
         [0031]    The analog inputs AD are connected through signal conditioning circuits  437  and buffer  438  to an A-D converter  440  to the SPI bus  436 . The serial I/O port  441  connects SPI  436  to failsafe circuit  432  which is connected to relay drivers  433 . The relay drive  443  drives the relay  444 . The failsafe circuit  432  receives a failsafe signal from the controller  432 . Upon absence of the signal from  432 , the failsafe circuit  442  automatically resets the relay drivers  443  to deactivate the relays  444 . Coil current sensor  445  determines that the relays have been activated and provides a signal back to the controller  432  through serial I/O port  441  and  446 . The serial I/O port  446  also connects the SPI  436  through opto-isolator  438  to conditioning circuits  447  for the digital input ports DD.  
         [0032]    A powerup reset LVI  431  is connected to the controller  432  and the failsafe circuit and resets them on power up.  
         [0033]    The network interface  406  is illustrated in FIG. 6 and includes a master brake controller  450  connected by direct connect transceiver  451  to a direct connect network  452 . A power up restart  453  and memory  454  are also connected to the master brake controller  450 . Head end termination HETT is connected to the master brake controller  450  by optical isolators  455  and load  456 . As illustrated in more detail in FIG. 7, the load  456  is a resistor-capacitor combination which is connected across the trainline at the trainline connector  34  of FIG. 2. A rectifier  457  and signal detector  458  are also connected and through inductors to the trainline in parallel to the load  456 .  
         [0034]    An alternative embodiment of the signal detector  458  and its connection to the remainder of system is shown in FIG. 11. The front and rear end terminations HETT are connected by couplers  490  and  491  respectively to a multiplexer  492 . The multiplexer  492  connects one of the HETT&#39;s to the transceiver  493  under the control F/R of the wired throttle controller  473 . The transceiver  493  determines and provides packet detect signals PKT and band in use BIU to the controller  473 , which determines the presence of communication in the front HETT, rear HETT or both. The HETT controller may be a Neuron having only the transceiver portion programmed.  
         [0035]    The HETT circuitry works in conjunction with the trainline termination connector on each end of the locomotive and provides a means for detecting the communication signal on the trainline while at the same time terminating the trainline. Detection of the communication signal provides indication that the otherwise live trainline connector in the locomotive is connected and it is safe to energize the trainline. This is in addition to or in lieu of the automatic electric train safety interlock described in U.S. Pat. No. 5,673,876 to Lumbis et al.  
         [0036]    As illustrated in FIG. 6, the direct connect network  452  is connected through direct connect transceiver  459  and router  456  to a transceiver  461 . The transceiver  461  is connected by coupler  462  to the trainline. The transceiver  461  sends and receives signals to control the trainline power supply and the power supply and braking of individual cars. It also controls serialization and initialization. The transceiver  461  may be a PLT-10 from Lonworks. The powerup reset  463  is connected to the reset of the router  460  and through a switch or diode  466  to the reset of transceiver  461 . Packet detect circuit  464  is also connected to the packet input of transceiver  461 .  
         [0037]    A stuck transmitter circuit  465  is connected to the transceiver  461  and upon detecting that it is in the transmission mode, provides a transmit signal to the master brake controller  450 . If the transceiver  461  is in the transmission mode for too long a period, a DISABLE signal is issued by the master brake  450  to the reset input of the transceiver  461 . The diode  466  prevents the DISABLE signal from resetting the router  460 . The time period may be, for example, ½ a second.  
         [0038]    As illustrated in more detail in FIG. 8, a stuck transmitter circuit  465  has a current sensor  466  and a comparator  467  to compare the output of the current sensor to a reference value. The transceiver draws a greater current in the transmission than it does in the receiving mode. The reference value is selected between the transmission and receiving values. Coupler  462  is shown as a transformer.  
         [0039]    As shown in FIG. 6, the direct connect network  452  is connected through direct connect transceiver  468  and router  469  to a transceiver  470 . The transceiver  470  is connected through coupler  471  to the network FTTA or FTTB. The transceiver may be an FTT  10  from Lonworks. Two of these transceiver networks are shown. A power up reset  472  is connected to the transceiver  470  and the router  469 .  
         [0040]    A second controller  473  is connected via the direct connect transceiver  474  to the direct connect network  452 . It includes the memory  475  and a power up reset  476 . The second controller  473  performs a calibration of the transceivers on the trainline and in each of the cars using a level sense circuit  477 . The second controller  473  provides an indication of the relative signal strength of the communication signals from any node on the network.  
         [0041]    The controller  473  broadcasts a message to all nodes to turn off their transceiver. This would be through transceiver  461 . Then, the second controller  473  would command each of the nodes, one at a time, to transmit a calibration signal. The received calibration signal would be sensed by the level sense circuit  477  by the RXIN and packet detect circuit off the coupler  462  of transceiver  461 . The value of the signal is then transmitted by  477  to the controller  473 . This information can be used to determine the relative indication of the integrity of the trainline connectors with respect to the communication signal. Also, the termination of the quality signal is made with respect to the location of each node of the train. This takes into account the signal loss due to the communication path between the commanded node and the transceiver  461 .  
         [0042]    The detail of the level sensor circuit  477  is illustrated in FIG. 9. The received calibration signal at RXIN is filtered and signal conditioned. The first stage  478  includes a high pass filter with a gain which is adjustably controlled by the second controller  473 . It is followed by a third order low pass filter. A precision rectifier  479  then rectifies and filters the signal and provides it to a peak detector averager  480 . The output of the peak detector  480  is provided to an analog to digital converter  481 . Once the signal has been processed and converted and stored in neuron  482 , it transmits a signal ready to the second controller  473 . The second controller  473  then requests that the processed signal be transmitted. The pack detect in combination with the asynchronous clear signal triggers the ADC  481  to acquire the data from RXIN. A powerup reset  484  is connected to the neuron  482 .  
         [0043]    The trainline power controller  50  is shown in detail in FIG. 10. An I/O analog to digital converter  502  connects the trainline TL, trainline current TL/I, trainline status TL STATUS and a trainline fault signal FAULT through opto-isolators  504  to a controller  510 , which is a neuron, through opto-isolators  506  and  508 . The locomotive battery and terminals BTTY+, BTTY− are connected through level detector  512 , AD converter  514  and opto-isolators  516  and  518  to the controller  510 . Thus, controller  510  has all of the information on the trainline power supply  38  and the locomotive battery.  
         [0044]    The trainline TL is connected through transformer  520  to a transceiver  522  which is connected by bus  524  to the controller  520 . The power up reset  526  is connected to the controller  510  and through diode  528  to the reset of transceiver  522 . A current sensor  530  is connected to the transceiver  522 . The sensed current of the transceiver  522  is compared at comparator  532  to a preset reference to determine whether the transceiver  522  is in the transmitting mode. If it is in the transmitting mode, the signal TRANSMIT is provided to the controller  510 . If it is in the transmit mode too long, for example ½ a second, then the controller  510  through latch  534  provides a DISABLE signal to the reset terminal of transceiver  522 . The diode  528  prevents this DISABLE signal from resetting the controller  510 .  
         [0045]    A watchdog reset  536  receives a strobe signal from the controller  510 . If the strobe signal is not received in the timeout period of the reset  536 , a watchdog reset is provided to the controller  510  and the latch  534 . The latch latches outputs from  510  which include trainline power supply TPSOK, trainline light emitting diodes LEDTL and trainline on signal TLON. The TLON signal is used by the trainline power supply  38  to apply the 230 volts to the trainline. It also provides, through optical isolator  540 , a control signal switch  542  which provides the voltage V 24  to the trainline TL+ and TL−.  
         [0046]    V 24  received from the trainline power supply  28  is provided to voltage regulator  544  which provides internal voltages V 5  and V 10 . A second voltage regulator at the controller portion  510 . Regulator  546  receives the voltage signal V 15  from the trainline power source  538  and provides reference voltage V 5  to the I/O A to D converter  502 . Voltage regulator  548  receives voltage signal V 12  from the trainline power supply  38  and provides the referenced voltage V 5  to the level sensor  512  and the A to D converter  514 .  
         [0047]    Although the stuck-on transmission mode has been described with respect to the trainline communication controller  40  and the trainline power controller  50 , the same circuitry can be provided in the car control device  20 .  
         [0048]    Although the present invention has been described and illustrated in detail, it is to be clearly understood that the same is by way of illustration and example only, and is not to be taken by way of limitation. The spirit and scope of the present invention are to be limited only by the terms of the appended claims.