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how to control automation direct stepper motor (stp-drv-4850 and stp-mtrh-23079)


I'm trying to use labview to control my Automation Direct, stepper motor (stp-mtrh-23079) with the stp-drv-4850 controller. Everything works fine in SureStep but when I try to send the same commands with Labview, I have problems. The motor does turn but the setup commands (eg AC5, DE5, VE2, FL20000) don't seem to have any effect. No matter what series of commands I send it, it always turns the same direction, the same number of times and at the same speed.


Please refer to the attached diagram.


Thanks in advance for your help,

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Message 1 of 7

Hi Chad,


Do you getthe same behavior if you use hyperterminal or putty?



Joe Daily
National Instruments
Applications Engineer

may the G be with you ....
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Message 2 of 7

I am using a terminal program and the commands that I send through it work just fine.

Thanks for the suggestion,


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Message 3 of 7

Hi Chad,


Check the you are using\ codes in your string. You can do this by right clicking on the string constant

Joe Daily
National Instruments
Applications Engineer

may the G be with you ....
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Message 4 of 7

I stumbled across this old thread when I was trying to solve the same problem with a STP-DRV-4850.  I finally ran Sure Step with a USB bus monitor running and discovered that when you open the SCL terminal, it sends the command "HR" to the driver, and when you close the terminal it sends a "QT".  I cannot find this documented anywhere, but it solved my problems.  Open a session with "HR" and all of the commands seem to work as documented.


LV 2013
Message 5 of 7



Did you ever figure out how to use the drive through the VISA test panel?


I have been trying by writing the serial commands to it (DI200, FL), but nothing happens on the drive's side although it says it is correctly reading/writing to it.




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Message 6 of 7



This forum post is from 2011 so it would be a good idea to post another thread so you would get more traffic.



Kurt P
Automated Test Software R&D
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