Hello folks.

I intend to use a microcontroller to run an on screen digital positioning display (OSD) but need to know something of the nature of the pulses sent to the stepper driver and/or the stepper motor.

As I understand the basic principle, the CNC Controller sends a specific number of pulses corresponding to the degree of rotation (200 steps/1.8 degrees) of the stepper motor to the stepper driver,. Then the driver reduces the angle of rotation by a number of microsteps according to the DIP switch settings on the driver. For example, a single pulse that would turn the motor 1.8 degrees, would after going through the driver, provide 0.18 degrees rotation if the DIP switches were set to 10 microsteps.

The direction of rotation is controlled by a high or low potential on the 'DIR' input to the stepper motor driver at the same time as the 'STEP' pulse is sent to the driver (I understand that Mach 3 gives the option of choosing either high or low for the 'DIR' signal).

Assuming that I am correct in the foregoing, I would like to know whether the 'DIR' signal from the CNC Controller is in the form of a pulse of the same duration as the step pulse or whether it is a continuous signal for the duration of the series of steps? My reason for asking is that I would like to use the 'DIR' signal to either increment or decrement the pulse count in the microcontroller.

Presumably I would need to provide some sort of isolation if using the driver outputs to limit the power to the microcontroller inputs such as opto-couplers?

I hope that someone can help me and thank you in advance.

Similar Threads: