SimonD

Curt, Many thanks for the clarifications... I will try and find out how the system is currently programmed. The "hunting" is my guess as to what is happening on the system. It is either that or the speed of the motor is unfortunately close to the natural frequency of the loaded system. Is there an easy way to tell if the motors are being run as steppers or brushless servos? Thanks Simon

Thanks for the prompt reply... I had a quick read but will need to digest it further. I suspect the system is working too hard. The mechanics were designed so that full steps provided more than adequate resolution. Thanks Simon

Just a couple of questions regarding closed loop steppers on the PMAC. Does the PMAC do microstepping, if so where do I set the microstep size or does it base the microstep size based on step frequency? In a closed loop using a linear encoder. Does the PMAC tell the motor to step until it says stop or tell the motor to go a set number of motor steps and then just report the positional error? If the resolution of the encoder is smaller than the minimum step size will this cause "hunting" as the controller will be asking for an intermediate position which cannot be achieved with the steps?