Brake Enable/Disable Delays

[ZLLentz]

I've encountered the first instance of a brake signal disengaging the brake before the motor has a chance to enable. This causes the stage to slip down because the holding current is not applied in time to counteract the vacuum load. In all other instances so far the motor enable has been much faster, to the extent that the enable delay in the EL7041 was the only parameter that needed to be adjusted.

We will need to add settings where you can configure how long the PLC waits between noticing that it should engage/disengage and applying/removing the voltage.

These parameters would need to be picked empirically such that:

• The brake disengages after the holding current is applied, but before the motor starts running
• The brake reengages after the move is completed, but before the holding current is released

You would set these in parallel with the CoE parameters. I'm not sure if we need to provide drive enable/disable delays in the settings as well.

[ZLLentz]

It's possible that the timing desynchronization between the NC process and the PLC process is very closely linked to the timing here, in which case we'll need to keep that in mind too and always delay with respect to the NC process. In the stage I'm using right now it completes the brake disengage and move about 1/4 of the time, which implies that sometimes the brake signal is sufficiently delayed by the 8ms difference between the two cycle times.

[ZLLentz]

Another approach may be looking for a better way to delay the move start so we do this in stages:

1. Send enable
2. Read enable (directly check the terminal current?)
3. Delay
4. No brake
5. Delay
6. Trigger move
7. Move done
8. Delay
9. Yes brake
10. Delay
11. Send disable
12. DMOV

It would also help to properly reset the setpoint once the brake is engaged so that the motor isn't trying to move before the move request.