9218 Doesn't Produce Excitation Voltage

Updated May 3, 2018

Reported In

Hardware

  • NI-9218

Driver

  • NI-DAQmx

Issue Details

I am using a 9218 and I can't get it to produce an excitation voltage from its Vex lines when set to use the internal excitation source.

Solution

  1. Test 1st by using a new task in NI-MAX before testing in other software
  2. Verify settings in MAX. In the Device tab, excitation source should be set to Internal
  3. Verify Voltage source. In order to provide internal excitation, the module requires a voltage source through the Vsup pins. Verify that you are providing sufficient voltage to these lines according to the 9218 Getting Started Guide. Verify that there is a good connection between the power supply and the Vsup channels.

Additional Information

Some task types (such as bridge and strain tasks) have select voltage values that they are able to provide. Voltage and current input tasks allow for the excitation voltage to be user selectable up to the 12V max. 

The 9218 also has the option to use n external power supply. In this case, the external supply is connected directly to the sensors voltage supply lines and does not go through the 9218 module.
 

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