Dynamic Brake/Coast Modes?

[s1900ahon]

Originally Posted by Al Skierkiewicz

Any speed controller that has a brake/coast jumper can have that jumper connected to a digital I/O and be controlled in software. We have done it many times in the past.

This concept has always bothered me, a bit, for a couple of reasons:
1. On the Jaguar, the BRAKE sensor pin (middle one) is a direct input to the MCU which has 3.3V IOs (which are 5V tolerant, but still). In retrospect, we really should have put an ESD suppression device on that pin (he says looking at the last version of the schematics).

But more so,
2. When you've done this in the past, did you also connect ground? I.e. Was the DIO connection to the brake/coast jumper 2 wires (signal+ground), or just one wire (signal only)? I presume you did single wire. I ask since the PWM input of motor controllers use optoisolators so that the only ground return from the motor controller is V-. Connecting to the brake/coast jumper with 2 pins introduces a second ground return which may bear more current should the V- get disconnected, even momentarily.

I don't recall seeing any documentation for how to do the dynamic brake/coast. I don't recall providing this in the Jaguar docs. I don't recall seeing it in the Victor (but that was a while ago for me).