Controller Anti-Lock Brake (Cab)
The controller anti-lock brake (CAB) is a microprocessor-based device that monitors wheel speeds and controls the anti-lock functions.
The primary functions of the CAB are:
- monitor wheel speeds
- detect wheel locking tendencies
- control fluid pressure modulations to the brakes during anti-lock stop operation
- control the ABS warning indicator
- monitor the system for proper operation
- provide communication to the DRBIII(R) while in diagnostic mode
- store diagnostic information in non-volatile memory
The CAB continuously monitors the speed of each wheel. When a wheel locking tendency is detected, the CAB will command the appropriate HCU valve to modulate brake fluid pressure to that wheel. Brake pedal position is maintained during an anti-lock stop by being a closed system with the use of 3 accumulators. The CAB continues to control pressure in individual hydraulic circuits until a wheel locking tendency is no longer present. The CAB turns on the pump/motor during an anti-lock stop.
The anti-lock brake system is constantly monitored by the CAB for the proper operation. If the CAB detects a system malfunction, it can disable the anti-lock system and activate the ABS warning indicator. If the anti-lock function is disabled, the system will revert to standard base brake system operation.
The CAB inputs include the following:
- four wheel speed sensors
- brake lamp switch
- ignition switch
- battery voltage
- diagnostic communication (PCI BUS) The CAB outputs include the following:
- six valve/solenoid drivers
- pump/motor actuation
- ABS warning indicator actuation
- red brake warning indicator actuation
- diagnostic communication (PCI BUS)