Incorrect Data Acquired from 9234 Module

Updated Feb 21, 2018

Reported In

Hardware

  • NI-9234
  • NI-9233

Software

  • LabVIEW

Issue Details

I am using a NI 9234 with a cRIO. When I give a +5V DC signal to one of the channels of the module, I see the value rising to +5V and falling down to 0V. Why is this happening?

Solution

The 9234 module have different filters which can be configured in the LabVIEW project. Each channel in the 9234 module can be configured in the following coupling modes - 
  • AC Coupling - AC signals are acquired, DC component is filtered.
  • IEPE AC Coupling - AC signals are acquired along with the IEPE Signal Conditioning, DC component is filtered.
  • DC Coupling - No filtering
In case you provide a DC signal to the 9234 channels in AC coupling, the DC component is filtered and this drop in signal can be seen. Follow the below steps to change the coupling modes - 
1. Open the LabVIEW project explorer containing the 9234 module and its application.
2. Right click on the 9234 module, select Properties.  


3. Change the coupling mode as per your requirement, in this case, change to DC coupling to acquire any DC signals in the channels.

Note : In case you are using a IEPE sensor, you need to select the IEPE coupling mode. Refer to IEPE Signal Conditioning to know more about it.

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