Traditional DAQ Excitation on 1520 Strain not active

[icebear]

I am using traditional voltage channels to acquire full bridge strain data.  I have an application that is acquiring load cell data from a 1520, it has been configured for 10 V excitation, yet a DMM reading the excitation reveals it is not active.  I can get excitation if I create a DAQmx channel, but when I now acquire the signals through the 1314/1520 the values are off (almost a factor of 2, for a 20 mV precision input I get a 40 mV reading on the DAQ card, not true if excitation is off).  How can I enable the excitation through traditional channels, this setup worked for a time (the what changed question is a good one, but unfortunately not easily answered, so I am just trying to move forward)?  I have tried swapping out the 1520 and have the same results.  I've tried just creating a strain channel for traditional DAQ with excitation, but no excitation is coming on even after attempting to acquire the strain data through the test panels. 

[jschwartz]

Hi icebear,

I have found a couple of KnowledeBase Articles that might be helpful in troubleshooting the excitation voltage of your 1520.

Configuration and Test of Excitation Voltages Using the SCXI 1520 in Traditional NI-DAQ

The Excitation Voltage from My SCXI-1520 Does Not Match It's Configured Value

How Can I Test the Voltage Excitation Level of an SCXI-1520?

If you follow all these steps and have tried several channels and you are still seeing incorrect values, your card may be damaged.  If you would like to send it in for repairs, you can create a service request at ni.com/ask then call 1-866-275-6964 to speak with an Applications Engineer.