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can I use both variable power supplies from ELVIS?

I am fairly new to Labview. I am trying to use both variable power supplies (one at a time) to power a DC motor while using an opto interrupter at analog input 0 to compute the RPMs of the Motor. I want to be able to adjust the Variable Power Supplies (both positive and negative) inside Labview (i.e. not manually). 
The DC motor requires ~85mA to run. I was able to use both the variable power supplies (controlled in Labview) earlier but I got this error a few times but it would still run fine:

Error 8 occurred at New File
Possible reason(s):
LabVIEW:  File permission error.
NI-488:  DMA hardware error detected.
Nothing has changed except Now get this error and it won't run at all:
Error -9320 occurred at NI ELVIS VPS -
Possible Resaons:
NI ELVIS: COMMUNICATIONS switch on the NI-ELVIS benchtop workstation is set to BYPASS, or the specified refnum type is invalid.
I even went back to my old Vis that worked and I now get the error. I've swithced out hardware and conclude something must be wrong with my use of the supplies. The NI ELVIC DC MOTOR SPEED vi provided by Labview's site now works though (no bybass error there?) The only difference between mine and it is that I am trying to control the variable power supply through labview instead of manually controlling it.
Please Help! I have been working on this for days.
p.s. I am attaching my dual VPS VI that did work but now gives me that second error too. 😕
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Hi Cozykat,

I took a look at your VI and noticed that you are specifying your device through a constant on the block diagram.  Have you seen this KB?  It mentions that error 9320 sometimes occurs when you specify the incorrect device.  You mentioned in your post that you have swapped hardware, so your device number may have changed.  You can use Measurement & Automation Explorer to determine the device number of your DAQ card by expanding the Devices and Interfaces folder and looking in NI-DAQmx Devices (if your DAQ card is a DAQmx device) or in Traditional DAQ Devices folder (if your card is a Traditional DAQ device).  Please let me know what DAQ card you are using and if changing the Device Number helps. 


Nicholas B, National Instruments

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