I'm driving a NEMA34 bipolar geared stepper motor with the following specifications: Rated Current 4A, Voltage 24-60V. It is being driven by a MA860H driver with output current of 2.6-7.2A 24-80VAC. I have the driver configured for a peak current of 4.45A, and using a microstep of 5 (1000 pulses / rev). This is connected to a gearbox that results in an input of around ~4000 steps / rev.
The driver is being controlled by a PLC that drives the stepper motor to a desired position. The motion control allows for a desired position, steps/second, and a ramp up/down time (ms).
This particular use case requires a new motion command to be issued while the motor may be in travel. There are no issues if i move the motor from standstill, or issue a new move command while the motor has reached its max steps/second.
However, if the motor is moving, and is nearing its desired position, it will begin to ramp down, if during this ramp a new move command is issued with an increased desired position, the motor should ramp back up and continue to move. Instead, the motor will seize up and makes a high pitch squeal. The longer i set the ramp-up/down time the easier this condition is to reproduce. Oddly enough if i perform the same function but the new move command tells the motor to reverse, this condition does not occur.
I'm not sure what the exact issue i am facing, or how to narrow it down to a particular component. Could it be counter EMF from the motor that is causing the strange behavior, or have i sized the motor incorrectly?