On-board integrated vehicle control and communication system

We claim:

1. An on-board control and communication system for use on a vehicle, said vehicle being operable as a single unit or being coupled to at least one other vehicle to form a train, one of said vehicles in said train operating as a master for controlling the operation of said train and the other vehicles in said train operating as slaves responsive to said master, each of said vehicles including a control and communication system, comprising:

at least one slave control means responsive to command signals and controlling a sub-system of said vehicle in accordance with said command signals;

master control means connected to said slave control means via a communication link, said master control means generating said command signals upon reception of an enabling signal and in response to desired vehicle operation information, said communication link being coupled to the communication link in other vehicles when vehicles are coupled to form a train;

detection means for detecting when said vehicle is coupled to another vehicle to form a train and for detecting the vehicle in said train designated as said master; and

conversion means in communication with said detection means for generating said enabling signal when said vehicle is designated and operates as said master, said slave control means on each of said vehicles further including pre-programmed sub-system operation information stored therein and executing said operation information upon loss of communications with said master control means to control the sub-system in the absence of command signals generated by the master control means.

2. The system as defined in claim 1, wherein said master and slave control means are in the form of microprocessor based controllers, the master controller on the vehicle designated as the master creating an address list including each master controller on vehicles operating as slaves in said train and each slave controller on vehicles in said train, said master controller also including means to monitor said train to determine the number of slave vehicles connected thereto and means for automatically revising said address list upon coupling or uncoupling of a vehicle to or from the train.

3. The system as defined in claim 2 wherein said communication link is in the form of a multiplex communication link.

4. The system as defined in claim 3 wherein said multiplex communication link is formed from a pair of twisted conductors.

5. The system as defined in claim 3, wherein each of said master and slave controllers is coupled to said multiplex communication link in parallel, said master controller and slave controllers on each vehicle receiving all of said command signals generated by the master controller in said train, said command signals being addressed by said master controller to a particular slave controller, said slave controllers responding only to command signals addressed thereto.

6. A train comprising:

at least two interconnected vehicles, one of said vehicles operating as a master and controlling the operation of said train, the other vehicles operating as slaves and being responsive to said master, each of said vehicles comprising:

a communication link linking with the communication link in the other vehicles froming said train;

control means operable to control the operation of said train when said vehicle is designated as said master and operable to control subsystems on said vehicle in response to commands generated by said master when said vehicle is designated as a slave;

request means in communication with said control means and being enabled when said vehicle is operating as a slave, said request means generating a master request signal in response to a master role change request;

detection means enabled when said vehicle is operating as said master and operable to detect a master request signal generated by the request means on a vehicle operating as a slave; and

conversion means for converting said master to a slave upon detection of said master request signal and converting said slave to said master upon generating of said master request signal automatically without disabling said train, said control means further including pre-programmed sub-system operation information stored therein, said control means on said vehicles operating as slaves executing said operation information upon loss of communications with said master to control the sub-systems in the absence of commands generated by the master.

7. The train as defined in claim 6 wherein said control means comprises a master controller and at least one slave controller, said slave controller being responsive to command signals generated by a master controller to control a pre-determined function of said vehicle, the master controller being operable to control the overall operation of said vehicle, wherein the master controller of said vehicle operating as said master generates command signals to control the vehicles in said train, the master controllers in the slave vehicles functioning as slaves responsive to said master.

8. The train as defined in claim 7 wherein said master and said slave controllers are interconnected via a multiplex communication link, said multiplex communication link in each of said vehicles in said train being interconnected.

9. The train as defined in claim 8 wherein said master controller in the vehicle operating as said master assigns an address value to each of the other master and slave controllers on said train, said master controller operating as said master providing said command signals with an address, said controllers responding to said command signals only when the address of said command signal corresponds with the address value assigned to said controller.

10. The train as defined in claim 9 wherein said master role is transferable between said vehicles upon generation of said master request signal by a master controller located on a vehicle operating as a slave, said master controller on said master vehicle assuming a slave role upon receipt of said master request signal, said master controller on said slave vehicle assuming said master role upon generation of said master request signal and generating a new address value for each of said controllers in said train.

11. The train as defined in claim 10 wherein said slave and master controllers are in the form of microprocessor based circuits.

12. The train as defined in claim 11 wherein said master controller in the vehicle operating as said master continuously monitors the number of vehicles in said train and re-assigns an address value to each of said controllers in said train upon removal or addition of a vehicle to said train.

13. An on-board control and communication system for use on a vehicle comprising:

operator control means operable to control the operation of said vehicle in response to commands received from an operator;

automatic control means operable to control the operation of said vehicle in a pre-programmed manner;

mode selection means in communication with said operator control means and said automatic control means, said mode selection means being operable between first and second conditions to enable one of said operator control means and automatic control means;

monitoring means monitoring said mode selections means to detect actuation of said mode selection means from one condition to the other condition, said monitoring means automatically enabling the control means associated with said other condition and disabling the control means associated with said one condition without disabling said vehicle upon actuation of said mode selection means from said one condition to said other condition; and

means to enable said automatic control means and disable said operator control means independent of said mode selection means upon malfunction of said operator control means.

14. A control and communication system as defined in claim 13 further comprising a second operator control means, said first and second operator control means being located at opposite ends of said vehicle and each having mode selection means associated therewith, each of said mode selection means being operable to select one of said automatic control means and said associated operator control means.

15. A control and communication system as defined in claim 14 wherein said operator control means includes an operator console and said mode selection means is a mode selection switch disposed on said console, said switch being moveable between first and second positions to select one of said automatic and operator control means for said vehicle, said monitoring means detecting movement of said switch between said positions.

16. A control and communication system as defined in claim 15 wherein said automatic control means is in the form of a vehicle on board controller, said controller including memory means for storing pre-determined vehicle operation information and controlling said vehicle in accordance with said information when said mode selection switch is positioned to select said automatic control means or when said automatic control means is enabled due to malfunction of said operator control means.

17. A control and communication system as defined in claim 15 further including a modular microprocessor based circuit in communication with each of said operator consoles and said vehicle on board controller, said microprocessor based circuits being interconnected via a communication link and including software for monitoring said mode selection switches and the operation of said operator control means thereby constituting said monitoring means and said means to enable said automatic control means.

18. A control and communication system as defined in claim 17 wherein said operator console generates a mode change signal upon actuation of said mode selection switch between said positions, said microprocessor based circuit associated with the control means selected by the mode selection switch detecting said mode change signal and enabling the control means associated therewith, the microprocessor based circuit associated with the previous selected control means disabling said previously selected control means.

19. A control and communication system as defined in claim 17 further including a plurality of sub-systems connected in parallel to said communication link, said sub-systems being operable to control a pre-determined function of a vehicle in response to control signals generated by said enabled control means, said enabled control means assigning an address to each of said subsystems and addressing each of said control signals, said sub-systems responding only to control signals addressed thereto.

20. A control and communication system as defined in claim 19 wherein said enabled control means and each of said sub-systems include count means, said enabled control means having a count means associated with each of said sub-systems and incrementing the count means associated with a sub-system to which a control signal has been sent, the value of the count means being transmitted to said sub-system with said control signal, said sub-system incrementing said count means upon reception of each control signal received that is addressed thereto and comparing the value of the count means with the transmitted value to detect messages transmitted by the enabled control means not received by said sub-system.

21. A control and communication system as defined in claim 20 wherein said sub-systems include memory means storing pre-determined operation information, said sub-system executing said operation information when said transmitted value differs from the value of said count means by a value greater than a threshold value.

22. A control and communication system as defined in claim 19 wherein said sub-systems include memory means storing pre-determined operation information, said sub-system executing said operation information to control said function upon isolation of said sub-system from said enabled control means due to failure of said communication link.

23. A train comprising:

at least two interconnected vehicles, one of said vehicles operating as a master and controlling the operation of the train, the other of said vehicles operating as slaves and being responsive to said master, said master including control means generating commands addressed to particular slaves, each of said slaves including control means responsive to commands generated by said master which are addressed thereto, said master vehicle including monitoring means for continuously monitoring said train to determine the number of vehicles in said train and generating an address list including each of said detected vehicles in said train and update means for updating said address list automatically upon addition or subtraction of a vehicle to or from said train without impeding control of said train by said master.

24. A train as defined in claim 23 wherein said master includes a count means associated with each of said slaves and each of said slaves includes count means, said master incrementing the count means associated with the slave to which a command has been sent, the value of the count means being transmitted to said slave with said command, said slave incrementing said count means upon reception of each command received that is addressed thereto and comparing the value of the count means with the transmitted value to detect messages transmitted by the master not received by the slave.

25. The train as defined in claim 24 wherein said slaves include memory means storing pre-determined operation information, said slaves executing said operation information when said transmitted value differs from the value of the count means at said slave by a value greater than a threshold value.

26. An on-board vehicle control and communication system for use on a vehicle comprising:

a master controller in the form of a microprocessor based circuit responsive to vehicle operation signals representing desired vehicle operation, said master controller generating command signals in response to said vehicle operation information;

at least one slave controller in the form of a microprocessor based circuit and controlling the operation of a subsystem on said vehicle;

a communication link interconnecting said master and said at least one slave controller, said slave controller being responsive to command signals generated by said master controller and controlling the operation of said subsystem in accordance with said command signals, said at least one slave controller further including sub-system pre-programmed operation information therein and executing said operation information upon loss of communications with said master controller.

27. The system as defined in claim 26 wherein said pre-programmed operation information is in the form of a plurality of executable programs, each program being associated with a specific fault in said system resulting in the loss of communications, said slave controller executing one of said programs when said associated fault is detected.

28. The system as defined in claim 27 wherein one of said specific faults includes the isolation of said slave controller from said master controller, said slave controller executing the program associated with said one fault and controlling the operation of said subsystem in a preprogrammed manner in the absence of command signals from said master controller.

29. The system as defined in claim 28 wherein another of said specific faults is the loss of command signals generated by said master controller over said communication link, said slave controller executing the program associated with said fault to inform said master controller that command signals generated thereby are not being received by said slave controller.

30. The system as defined in claim 28 further including a plurality of slave controllers each controlling a sub-system of said vehicle, at least one of said slave controllers including said program associated with said one fault.

31. The system as defined in claim 30 wherein each slave controller controlling a sub-system associated with a vital function of said vehicle includes a program associated with said one fault.

Description Submit all comments and votes

The present invention relates to control systems and in particular to an on-board integrated vehicle control and communication system.

On-board control and communication systems for use in vehicles are known in the art. Traditionally, vehicles such as for example subway train cars and light rapid transit (LRT) cars have been designed so that they can be operated as a single independent unit or can be coupled to other vehicles to form a train. Generally, each car is provided with a bulky and expensive control and communication system. These control and communication systems typically include a large hardware based central controller which communicates with a plurality of hardware based vehicle sub-control units. The central controller is connected to each vehicle sub-control unit via a coupling connector and a plurality of cables, each cable housing a large number of copper wires. The vehicle sub-control units operate the various systems in the vehicle such as for example, the door operation system, the HVAC system, the vehicle propulsion unit, etc. in response to control signals received from the central controller.

When a plurality of vehicles are connected to form a train, one of the vehicles, normally the lead vehicle, is designated as the master. The central controller in the designated master controls the movement of the train as well as the operation of the sub-control units in each of the vehicles.

However, a problem exists in these control and communication systems. Since there are a plurality of sub-control units disposed on each vehicle and since a number of large cables are required to connect each sub-control unit through vehicle coupling connectors to the central controller, this type of on-board control and communication system is expensive and prone to malfunction. Furthermore, another problem exists in that since the large hardware components and bulky wiring must be housed in the vehicle, the revenue capacity of the vehicle is reduced. Furthermore, still yet another problem exists in that if the designated master fails, the train becomes disabled until the designated master is manually disabled from the master role and another vehicle is designated as the master.

It is therefore an object of the present invention to provide a novel vehicle control system.

According to the present invention there is provided an on-board control and communication system for use on a vehicle, said vehicle being capable of operating as a single unit or being coupled to at least one other vehicle to form a train, one of said vehicles in said train operating as a master for controlling the operation of said train and the other vehicles operating as slaves responsive to said master, each of said vehicles including a control and communication system, said system comprising:

at least one slave control means responsive to command signals and controlling a sub-system of said vehicle in accordance with said command signals;

master control means connected to said slave control means via a communication link, said master control means generating said command signals upon reception of an enabling signal in response to desired vehicle operation, said communication link capable of being coupled to the communication link in other vehicles when vehicles are coupled to form a train;

detection means for detecting when said vehicle is coupled to another vehicle to form a train and for detecting which of said vehicles in said train is designated as said master; and

conversion means in communication with said detection means for generating said enabling signal when said vehicle is detected as being said master.

Preferably, the control means includes a microprocessor based master controller and a plurality of microprocessor based slave controllers, each slave controller being responsive to command signals received from the master controller. The slave controllers control the various sub-systems in the vehicle in response to the command signals.

In another aspect of the present invention there is provided an on-board control and communication system for use on a vehicle comprising:

operator control means operable to control the operation of said vehicle in response to commands generated by an operator;

automatic control means operable to control the operation of said vehicle in a pre-programmed manner;

mode selection means in communication with said operator and automatic control means, said mode selection means being operable between first and second conditions to enable one of said operator or automatic control means; and

monitoring means for monitoring said mode selection means, said monitoring means detecting conditioning of said mode selection means from one condition to the other condition, said monitoring means automatically enabling the control means associated with said other condition and disabling the control means associated with the one position without disabling said vehicle.

In still yet another aspect of the present invention there is provided an on-board control and communication system for use on a vehicle comprising:

at least one slave control means responsive to command signals and communicating with a sub-system of said vehicle, said slave control means operating said sub-system in accordance with said command signals

master control means connected to said slave control means via a communication link, said mater control means controlling the operation of said vehicle and generating said command signals in response to desired vehicle operation, said master control means communicating with an operator console or a preprogrammed controller and receiving signals representing said desired vehicle operation therefrom whereby each of said master and slave control means one in the form of a modular micro-processor based circuit and wherein said communication link is a multiplex communication channel.

Preferably, the master and slave control means are in the form of remote control interface units (RCIUs) comprising a modular microprocessor based circuit to facilitate the replacement thereof if required.

In still yet another aspect of the present invention there is provided a train comprising:

at least two interconnected vehicles, one of said vehicles operating as a master and controlling the operation of said train, the other vehicles operating as slaves and being responsive to said master, each of said vehicles comprising:

a communication link operable to engage with the communication link in another vehicle when vehicles are interconnected to form a train;

control means capable of controlling the operation of said train when said vehicle is designated as said master and operable to control said vehicle in response to commands generated by said master when said vehicle is designated as a slave;

request means in communication with said control means and being operable when said vehicle is operating as a slave, said request means generating a master request signal in response to operation control;

detection means for detecting said request when said vehicle is operating as said master; and

conversion means for converting said master to a slave upon detection of said request and converting said slave to said master upon generating of said request automatically without disabling said train.

In still yet a further aspect of the present invention there is provided a train comprising:

at least two interconnected vehicles, one of said vehicles operating as a master and controlling the operation of said train, the other of said vehicles operating as slaves and being responsive to said master, said master including control means generating commands addressed to particular slaves, each of said slaves including control means operable in accordance with commands generated by said master addressed thereto, said master vehicle including monitoring means for continuously monitoring said train to determine the number of vehicles in said train and generating an address list including each of said detected vehicles and update means for updating said address list automatically upon addition or subtraction of a vehicle from said train.

control means capable of controlling the operation of said train when said vehicle is designated as said master and operable to control said vehicle in response to commands generated by said master when said vehicle is designated as a slave.

The present control system provides advantages in that typical hardware control equipment is reduced and replaced by the RCIU software control. Furthermore, the typical bundled copper wire conductors are eliminated by the provision of the multiplex communication link. These provisions reduce wiring, costs, space requirements and complexity. Moreover, the present system standardizes the modules and interfaces in the vehicle since the various RCIUs differ only in software control and Input/Output counts. Also, the design of the communication link and the RCIUs accommodates expansion to allow additional vehicle control systems to be added to the system and controlled in a similar manner.

This design provides further advantages in that all of the signals for the train are conveyed over the multiplex communication link in a common readable form. These provisions allow any RCIU to assume the master role of a vehicle and also allow the master unit of a train to be automatically switched to another vehicle without disabling the train. Moreover, the software control allows nodes (vehicles) to be added to or subtracted from the train without adversely effecting train vehicle communications.

An embodiment of the present invention will now be described by way of example only with reference to the accompanying drawings in which:

FIG. 1 is a perspective view of a vehicle;

FIGS. 2a and 2b, are rear and front views of the vehicle illustrated in FIG. 1;

FIG. 3 is a side view of the vehicle shown in FIG. 1;

FIG. 4 is a block diagram of a control system used in the vehicle illustrated in FIG. 1;

FIG. 5 is a front view of a control panel provided in the vehicle illustrated in FIG. 1;

FIG. 6 is an illustration of a message transmitted by the control system shown in FIG. 4;

FIGS. 7 to 10 are flow charts illustrating the steps performed by the control system illustrated in FIG. 4; and

FIG. 11 is a block diagram of a prior art control system.

Referring to FIGS. 1 to 6, a revenue carrying vehicle 10 is shown. The vehicle 10 can be interconnected via mechanical and electrical couplers 12 located at both ends of the vehicle 10 to other similar vehicles to form a train. Each of the vehicles 10 includes a pair of trucks 14, 16, each truck being located at opposite ends of the vehicle 10. Each truck supports a pair of wheelsets 18, 20 spaced along the longitudinal axis of the vehicle 10. The wheelsets 18, 20 rest on the rails 22a of a track 22.

Each vehicle 10 is also provided with linear induction motor (LIM) primaries (not shown) which cooperate with a reaction rail 26 extending between the rails 22a of the track 22. The LIM primaries are operable to provide thrust to the vehicle 10 in a known manner. Since the operation of linear induction motors is well known in the art, the operation thereof will not be discussed any further herein.

In the embodiment shown, the vehicle 10 is similar to any common subway or light rapid transit car are includes at least one set of doors 28 on each side of the vehicle for allowing passengers to enter or other revenue to be placed in the vehicle 10. A door controller sub-system 30 is housed in the vehicle 10 and controls the movement of the doors 28 between open and closed positions in a known manner. A propulsion sub-system 32 and braking sub-systems 34, 36 are also disposed on the vehicle 10. The sub-systems 32 to 36 are also conventional and control the movement of the vehicle 10 in a known manner. Other sub-systems 38 such as a lighting sub-system and a heating, ventilation and air conditioning (HVAC) sub-system are included on the vehicle 10 to maintain environment control in the vehicle.

The vehicle 10 includes two operator manual console logic controllers 42 forming part of an integrated vehicle control and communication system (IVCCS) 40, the controllers 42 being located at opposite ends of the vehicle 10. A manual console 43 is located at each of the manual console logic controllers 42 to allow an operator to control manually or override the operation of the various sub-systems 30 to 38 disposed on the vehicle 10. Referring now to FIG. 5, one of the manual consoles 43 is better illustrated. The console 43 includes a throttle 43a and a vehicle speed indicator 43b which operate in a conventional manner. A mode selection switch 43c is included and allows an operator to select the mode of operation of the vehicle, the modes being manual (man), automatic (auto) and cab signalling (cab sig). Door open switches 43d are provided to allow the operator to control the door controller sub-system 30 so that the doors 28 may be moved between open and closed positions. Various indicator lights 43e are provided along with other conventional controls to allow an operator to control all aspects of the vehicle 10.

The manual console logic controllers 42 communicate with the consoles 43 and interpret operation of the console controls in a known manner. The console logic controllers 42 in turn generate control signals in response to actuation of the various console controls. If the automatic mode of operation is selected for the vehicle, both manual console logic controllers 42 and consoles 43 are disabled until a new mode of operation is selected by moving the mode selection switch 43c at an active console 43 to another position (i.e. man or cab sig). Control of the vehicle in the automatic mode is carried out by a vehicle on-board controller (VOBC) 46. The VOBC 46 includes a memory which stores pre-determined vehicle operation information. The VOBC 46 generates control signals in response to the pre-determined operation information to control the vehicle 10 in a pre-determined manner.

When the manual or cab signalling mode is selected via the manual console 43 at one of the manual console logic controllers 42, the operation of the vehicle 10 is controlled by the operator stationed at the manual console. However, during the cab signalling mode, although the operator controls the operation of the vehicle 10, the VOBC 46 conveys the pre-determined operation information to the console 43 to allow the operator to see the manner in which the vehicle is programmed to operate.

The manual logic controllers 42 are interconnected via a hardwire (vital signals) link 44. The hardwire link 44 also extends to the vehicle on-board controller (VOBC) 46. Each of the manual console logic controllers 42 and the VOBC 46 are as mentioned previously conventional vehicle systems and are in communication with individual remote control interface units (RCIU) 48. The RCIUs 48 receive the control signals generated by the console logic controllers 42 or the VOBC 46 depending on the selected mode of vehicle operation and condition the control signals before they are transmitted to the various sub-systems 30 to 38 on the vehicle 10 as will be described. The RCIUs 48 in communication with the console logic controllers 42 and the VOBC 46 are interconnected via a multiplex communication link 50 comprising a shielded twisted copper pair.

The communication link 50 extends from the RCIUs 48 across the length of the vehicle 10 to interconnect each of the couplers 12. This permits the communication link 50 of one vehicle 10 to be connected to the communication link 50 of another similar vehicle when two or more vehicles are interconnected to form a train. The communication link 50 also extends to a plurality of other RCIUs 52 disposed on the vehicle 10, each of the other RCIUs 52 being associated with one of the vehicle sub-systems 30 to 38. Each RCIU 52 is connected to its associated sub-system and provides control signals thereto so that the sub-systems can be operated in the desired manner. The hardwire (vital signs) link 44 also extends across the vehicle 10 to interconnect the two couplers 12 and extends to the door controller sub-system 30, the braking sub-systems 34, 36 and the propulsion sub-system 32. This permits emergency commands generated by the operating console logic controller 42 or VOBC 46 to communicate directly with these sub-systems on the vehicle 10.

Each of the remote control interface units (RCIUs) 48, 52 is in the form of a microprocessor-based circuit including an INTEL 8044AH integrated circuit (IC) implementing an INTEL 8044 "BitBus" serial data bus system. The INTEL 8044AH IC incorporates an INTEL 8046 micro-controller having an intelligent serial communication controller or serial interface unit (SIU). Resident firmware in the 8044 microcontroller manages task execution and interrupt handling through a multilevel priority structure. Functions which require near immediate attention are placed within tasks of high priority. Each of the RCIUs 48, 52 is substantially identical and of a modular design to facilitate the replacement thereof and to permit additional RCIUs to be connected to the communication link 50 without adversely affecting the system 40. The INTEL "BitBus" system is suitable for use in serial multi-node distributed intelligent systems and therefor possesses the necessary capabilities to permit structured communications along the communication link 50 between the RCIUs 48, 52.

Although known in the art, a brief description of the INTEL "BitBus" system is provided to clarify the operation of the IVCCS 40. The INTEL "BitBus" allows approximately 250 nodes to be interconnected and permits communications to occur between each of the 250 nodes. Communications between the nodes in the "BitBus" system are governed by a selected protocol which determines the rules of communications between the nodes. In the "BitBus" structure, one of the nodes in the system is designated as a master whilst the other nodes in the system are designated ass slaves. The protocol in the "BitBus" system allows the designated master to control all communications in the system.

Thus, the selected master node determines the operation of the slave nodes by supplying appropriate commands thereto. Each command generated by the master is addressed to a particular slave. The selected master allows the slave nodes to respond to the master to confirm execution of the command. Similarly when a slave replies to the master, the reply is addressed to the master so that only the master responds to the transmitted message. Accordingly, the protocol or message structure used in the "BitBus" system, pads a data message to be transmitted between two nodes with address information, error correction information and information concerning whether the transmitted data message is a command generated by the master or a reply transmitted by a slave. FIG. 6 illustrates a typical message structure transmitted along an INTEL "BitBus" system. When a message is generated by the master and received by the slave to which the message is addressed, the data message portion of the transmitted message is used by the slave node and the slave node executes the command. If message corruption occurs over the "BitBus" system, the transmitted message is ignored by all nodes in the system.

In the present system 40, each of the RCIUs 48, 52 are considered as nodes by the INTEL "BitBus" system and communications therebetween occur over the communication link 50. The master RCIU on a vehicle 10 is determined by the mode of operation selected by the mode selection switch 43c at active manual console 43. Thus, for a single vehicle 10, when the manual mode or cab signalling mode of operation signal is selected at an active manual console 43, the RCIU 48 connected to the console logic controller 42 associated with the console 43 is designated as the master node and controls all communications in the vehicle 10. When the automatic mode of operation is selected, the RCIU 48 connected to the VOBC 46 operates as the master node in the system 40. All other RCIUs 48,52 disposed on the vehicle function as slaves once a master has been selected.

When two or more vehicles 10 are interconnected to form a train, either the RCIU 48 connected to one of the manual console logic controllers 42 or the RCIU connected to the VOBC 46 on one of the vehicles 10 is designated as the master. All other RCIUs 48,52 in the train will assume a slave role. Since each of the RCIUs 48,52 are substantially identical, each RCIU disposed on a vehicle is capable of assuming the master role. However, in this embodiment only the RCIUs 48 are able to control the operation of the vehicle 10 completely. Thus, only these RCIUs are permitted to assume the master role.

The RCIUs 48 include an active variable which can be cleared and set and an active line in communication with the mode selection switch 43c at each console 43. The RCIUs 48 also include software for monitoring the active line to detect a change in state from low to high thereon which signifies that the selected mode of operation of the vehicle 10 has been changed and that the RCIU 48 detecting the change of state on it's associated active line is to assume the master role. Moreover, the RCIUs 48 include software that permits the master role to be transferred between RCIUs when a change in the selected mode of operation is detected and permits the master RCIU to transfer the master role to another RCIU 48 without a request having been generated. The operation of the software will be described in more detail hereinafter. The RCIUs 48 also monitor the communication link 50 when two or more vehicles are interconnected to form a train to detect requests for the transfer of the master role by one of the RCIUs 48 disposed on one of the vehicles in the train.

Each of the RCIUs 48, 52 and particularly RCIUs 52 include pre-determined operation information which is stored in the memory therein. This information is used by the RCIU to control the sub-system connected thereto in accordance with the pre-determined operation information in the event of failure of the communication link 50 which isolates the RCIU from the master RCIU 48. This permits the vehicle 10 to operate without requiring shut down of the system 40 in the event of failure of one of the RCIUs (nodes) in the system. This is particularly useful when a non-critical sub-system becomes disabled from the master RCIU 48. It should be apparent that when a critical sub-system such as for example the propulsion or braking sub-systems 32 to 36, the pre-determined operation information causes the RCIU to control the sub-system in a manner to bring the vehicle to a stop.

Also, since the "BitBus" system is designed so that corrupted message transmitted between nodes over the communication link 50 are ignored by all nodes in the system, the RCIUs 48,52 are provided with software for detecting this type of data transmission failure. This allows the IVCCS 40 to determine message transmission failure that typically would not be detected in the "BitBus" environment and ensures that vehicle control is maintained at a high level. Details of this type of message transmission failure detection w