Sync DAQ measurements with motor controller

Hi all,
I've been grinding my head for days on this problem.
I've got an NI DAQ reading an analog voltage and a Maxon EPOS2 motor controller.
I want to read analog voltage from the DAQ at a frequency of 1800Hz and around 25 samples. For every set of samples, I want the EPOS2 motor controller to read its encoder position and have write to measurement file log all the data.
The problem I'm having is that although data values from the DAQ are recorded, they lag behind the encoder values provided by the EPOS2 by approx 50ms. This lag time changes as a function of the DAQ's rate and number of samples.
I attached an example data file. If you scroll all the way to the bottom, you'll see that the right most value (time from computer and I believe EPOS?) is different from the left most time value which came from the DAQ waveform.
I've attached my code to this post. Would some form of rendezvous or queue be applicable? Any thoughts would be most helpful.
Thanks
Attachments:
APS_linear1_5_stable.vi ‏137 KB
8_17_11_25s_1800Hz_150_2.txt ‏977 KB

Hello Ruben_D
I'm sorry this is causing you an inconvenience! Can you please provide a link to the EPOS2 install file as I seem to be missing a number of their dependent VIs. Thank you very much!
Sincerely,
Greg S.

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Dear apok,
Please see the attached view of my vi. I can not try to enter lower preload to match with what I really want, because it is unpredictable and it is not professional solution.
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Attachments:
Loadcell&MotorControl.png ‏286 KB

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Attachments:
ControlWord send.vi ‏26 KB

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problem.jpg ‏124 KB

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~~~~~~~~~~~~~~~~~~~~~~~~~~
"It’s the questions that drive us.”
~~~~~~~~~~~~~~~~~~~~~~~~~~

Send DAQ measurement results through serial ports

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Message Edited by Henrik Volkers on 07-13-2009 04:21 PM
Greetings from Germany
Henrik
LV since v3.1
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LabVIEW driver for a ControlTechniques motor controller

Anyone know of LabVIEW driver for a ControlTechniques
Unidrive motor controller?
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Any help much appreciated
Paul
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LV can interface to 232, 485, Devicenet... depending on what the controller has.
You could find a LV/CVI driver for this (232/GPIB/ethernet only) instrument at http://www.ni.com/devzone/idnet/default.htm . If it's not listed there, it leaves you with one of a couple options. First, I would like you to submit a request for this driver at: http://zone.ni.com/idnet97.nsf/instrumentdriverrequest/
We develop drivers based on demand and popularity so the more requests we have for it, the greater the possibility that we will develop one.
If you would like to try developing your own instrument driver (or modify the existing one), we have documentation, model instrument drivers, and driver templates to help at :
http://www.ni.com/devzone/idnet/development.htm
We also have a syndicate of third party vendors that specialize in National Instruments' products and services. Some of the vendors specialize in driver development. I would suggest contacting one of the Alliance members at:
http://www.ni.com/alliance
An instrument driver is a collection of functions that implement the commands necessary to perform the instrument�s operations. In short, someone read the instrument user manual and implemented some of the functionality in a program for the end user. Instrument drivers are not necessary to use your instrument. They are merely time savers to help you develop your project so you do not need to study the manual before writing a program. With all of this work already done for you in the driver, instrument drivers can significantly reduce development time.
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Some useful resources for your application are
ni.com > NI Developer Zone > Development Library > Instrument Connectivity
http://search.ni.com/?col=alldocs&layout=TechResources&ql=a , to search examples and knowledge bases
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Sync DAQ measurements with motor controller

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