stepper motor control
- Microstepping down to 1/64th.
- Digital inputs and outputs.
- 4 input lines, opto-isolated requires independent ground and power.
- 4 output lines, open collector requires independent ground and power, and a pull-up resistor where max sinking current is 200mA (Rpullup = VIO / Isink). A 1kOhm resistor seems fine for driving TTL loads or a 2N2222 transistor.
- Stopping the motor on a fractional step requires more hold current even if the motor is not under load. In other words, stopping between a full step is effectively a holding load.
- Position index units are always based on 1/64 of a step no matter which microstepping mode is set. In other words, the position index is independent of step size. This can be confusing at first. Set the step size to 1 (no microstepping); tell the controller to move to position 64; and it will move one full step. Tell the controller to move to position 32 and it will not move, but it will report the position as 32.
- There appears to be a bug in this controller that prevents it from moving to an odd position index. If you ask it to move to index 1001 it will move, but when you subsequently ask it the current position it will report 1002. This happens in all microstepping modes.
- Microstepping chopper waveforms are in the audio frequency range (20kHz) so a motor will make harmless squeaks and whines while moving and holding.