Thanks for the sanity check Henrik.

I appreciate your claim not to be a motor control expert but your experimental knowledge is still quantum leaps ahead of mine. I promise to take your comments on board and apply the concepts with due diligence in my designs

1/. OK, and understand. I need to redesign the power control PCB anyway because I want to move from phototransistor opto isolators to logic opto devices to reduce turn-on/turn-off times and thereby reduce dead-time.

2/. I thought that was the case - I just wanted to make sure there was a proven method of adjusting pid_Out around the 50% duty cycle setting.

3/. As described in my earlier post, potential for direction reversal will be eliminated by my program and instant stop available only in emergency situations.

I am aware that the rail voltage of my rectified mains power supply will be twice that of the treadmill motor. My original intention was to limit the PWM to 50% maximum such that the average voltage applied would be around the motor voltage rating. Yes, peak voltages will be higher but from my knowledge of treadmill motor drive configurations, these motors are used this way all the time. Actually, it was the fact that locked antiphase configurations only apply half rail voltage to the motor at any one time that sparked my interest to their use in my application - or have I got that concept all mixed up too?

Lots more reading and thinking to be done on my part but I will keep you updated with my progress milestones.

Cheers
Barry
VK2XBP