working with AB PLC5/40, we have a couple of vfd's that are controlled by flow until additional equipment is running and then control switches to pressure. I also want to be able to control vfd speed manually via HMI. I believe that this can be accomplished using the Set Output Mode (word 0 bit 4) and moving word 16 (CV output) from the active PID into word 10 (set output) of the inactive PID. If manual control is required from HMI then move the HMI manual output value into both the PIDs at word 10.
please let me know if this even in the ball park. I would also appreciate any links or example logic.
please let me know if this even in the ball park. I would also appreciate any links or example logic.