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Topic: Arduino appears to slow motor down (Read 1 time) previous topic - next topic


Relatively new to all of this but here goes:
I have:
Arduino Duemilanove
RSSM2 Stepper Driver card.
Astrosyn Y129 Stepper Motor

I have connected it all up and written a program in labview to control it. All seems to be working, however I notice I get a very small maximum speed from the motor. When I disconnect the arduino, and use the RSSM2's internal clock (by shorting the step rate input to the output) I can control the speed by the variable resistor. This gives a much greater max speed.
Is it the arduino that is slowing the speed down?
Any help appreciated.

Basically all i'm doing is sending high signals to the input via a labview loop. Another high/low signal controls direction and a high signal goes to the DIS input when my loop is complete, which in turn shuts off the motor.


How fast can your LabView code send pulses to the motor controller?


You would do much better to pass a delay value from Labview and get code on the Arduino to clock the step
input....   That controller boards says upto 2kHz input step clock, so you should only be limited by motor
and power supply voltage then.
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]


Sorry for the slow reply.
How would I find ouot how fast the labview code is passing pulses to the motor controller?
It really is a massive difference as to how fast the motor goes.

MarkT - I appreciate the reply,how would I go about doing that? I've just got the arduino sketch that allows labview to communicate with it and haven't edited it at all.



And you've also got the sketch that drives the motors direct from the Arduino (the one that
goes fast).  So you need to pass instructions of some form from Labview to the Arduino
that it then uses to control the motor.

The issue is the speed of the link from Labview to the Arduino - both raw data rate and the
OS's handling of driving the USB serial ports.  Without having a real-time OS this isn't something
you can fix I suspect (but do set the baud rate to maximum if it isn't already).
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]


I see what you mean.

However, When I run the motor fast, by shorting the clock input, I don't use the arduino. If I connect the arduino and upload a basic sketch, it also slows the motor down. This is why I suspect it's the arduino slowing it down as opposed to Labview

What do you think?

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