Question about relays: update frequency

[JJG13]

For the past couple of years the logic in my 26.2 ms loop area has looked like this:

GetData(&rxdata);
set all pwms to neutral and set all relays (fwd and rev) to 0
execute logic that sets pwms and relays
PutData(&txdata);

By setting all pwms and relays to neutral, I know that nothing will move if I don't set it and outputs from the previous pass won't interfere with the current pass. Also, if I need to put relay1 forward, all I have to do is write relay1_fwd = 1 and not worry about relay1_rev because I know it is set to zero at the beginning.

This year I realized that PutData handles the pwms(and a few other things) but not the relays. In fact, I have no idea how or how quickly the master processor sets the relays after it is set in code. This makes me think that my habit of resetting all relays at the start of each loop may not be such a good idea if enough time elapses between the time I set the relays to off at the start and I set the relays to what I want them to be to adversely effect the robot.

I've had no problems doing this so far but, in order to sleep soundly, I need to know how quickly the master processor processes what I set the relays to and if I will ever get burned by zeroing the relays before each pass.