So the Vigilance system is the way which the system gives an alarm to the driver if the pedal is being pressed but there has been no movement of the controls?
The DSD pedal is the instrument which allows the human to tell the machine that they're still alive and in control.
I take it that if the Vigilance is isolated but the DSD isnt, then the system just puts the emergency brake on when the pedal isn't pressed? So what happens if the DSD is isolated but not the Vigilance? I know its not normal practice but is that possible?
If the DSD wasn’t isolated by vigilance was, it would just be like normal driving (albeit without having to cancel vigilance*, with some rule book bits and pieces around degraded working, and certainly not in passenger service).
If DSD was isolated the pedal wouldn’t have any function and (I seem to recall from my traction course) this would stop you resetting the vigilance once triggered. For this reason we would isolate either both systems or only vigilance, but we would never isolate only the DSD.
*very rare to cancel the vigilance in metro driving as you’re constantly braking and accelerating. Different for mainline of course.
EDIT: and yes you’re right, vigilance can start beeping at you when the pedal is depressed. It is then necessary to release and depress the DSD pedal in order to cancel it. On the stock I sign moving the controls won’t cancel the vigilance once the beeping has started, although this seems to be stock dependent.
