Stepper motor unable to run above ~13kHz

[Joel Moore]

I'm not trying to blame my problems on the T100MD888+.  I just figured someone here might have some advice.

I've got an Anaheim 23MD series motor (combined stepper/driver deal) connected to my TriPLC.  Whenever I try to drive it with frequencies approaching 13, 14, 15 kHz and higher it won't spin but it does whine like it's spinning.

The motor specs claim the following:

Maximum clock frequency: 500 kHz
Minimum clock pulse width: 1.0 microseconds

I would think this motor would be sufficient to handle whatever the TriPLC can put out for a clock signal.

Maybe my power supply is the problem?  I'm using a Sola SDP4-24-100T (24V, 4.2A) to power the motor and the PLC.

Is this not uncommon?  What should I be targeting if I want to try to overcome this?

[support]

Although the PLC pulse generator can output maximum of 20000 pps, unfortunately at above 14KHz the waveform is not very square. Time spent in servicing other system interrupts become more significant so it could lengthen the period and that may be a reason why the stepper motor is not able to run. The T100MD+ generate stepper pulses using interrupt driven software technique and that is a trade off to keep the cost low. Try using gear to increase your speed and run the stepper at lower speed.

[Joel Moore]

I understand.  No big deal, really.  It's hard to criticize such a versatile piece of hardware.

I actually can just run my motor at quarter or half step rather than eighth if I need more speed.  That still leaves us with plenty of resolution for our application (.0002" to .0004" per step).

Thanks for the up front reply.