Brake Signal: Description and Operation

Brake Light Switch

There are two separate Hall effect brake-switch inputs into the EMS2000 to allow redundant integrity checking. The signal from the Main Brake switch is used in the control of both the Cruise Control and the Drive By Wire systems. If the brake is operated, the system shall suspend the cruise-mode, but shall retain any current valid target-speed in memory. The second switch is used in a safety plausibility check. If at any time the two brake signals are inconsistent, a fault condition is assumed and any accelerator demand will result in no throttle change and the engine will remain at its idle state.

Brake Light Switch Fault Symptoms
If the two brake signals are seen to be inconsistent at any time, a fault condition must be assumed. The accelerator pedal activation signal is set to zero, hence there will be no throttle demand and the engine will remain at idle. If this occurs while in a cruise active mode, the system shall suspend and will disable cruise for the remainder of that journey. The system will register a fault disallowing further operation.