Why does excitation voltage go to zero when strain gage is wired to SCXI module?

[Q Man]

I have a load cell that doesn't seem to work when I wire it to a SCXI 1320 adapter plugged into an 1121 module. The excitation voltage drops from 10v to 0v and the signal voltage remains at 0 when I apply a load to the cell.  I suspect that the excitation voltage dropping to 0v is the reson the cell isn't reading, nothing going in so nothing coming out,  but I don't know what would cause the excitation voltage to drop to zero. 

• I have tried all of the channels on the module with the same results. 
• I've checked the gain and filter jumper settings in the module and they match the settings in MAX.
• I have also wired the load cell to a process meter from another supplier and the cell works fine. Voltage does not drop and cell responds to loading.
• I've tried several different gain settings and checked to insure that the jumpers and the MAX settings were the same each time but still get the same results.

Voltage is being measured at screw terminals with multi meter. 

Any suggestions on why this is occurring and or how to fix it would be greatly appreciated.

Thank you,

Jason

[devchander]

Check the setings for following Jumpers 16, 26 ( channel 0), 24, 25(channel 1), 36,37 (channel 2)48,49(Channel 3)

also refer to the attached manual page: 2-11 for excitation level jumpersettings and see if they are correct

[Logan_K]

Also, the SCXI-1121 can't support a load of less than 800 ohms when using 10V of excitation, so you should try setting the excitation to 3.333V if using a load cell with less than 800 ohms of nominal resistance. You also might want to confirm that the excitation is set for voltage mode, instead of current mode. Those jumper settings are on p2-10 of the user manual.

Finally, do you have the correct bridge configuration setting for each channel? For a load cell, you should use the full-bridge configuration.

Regards,
Logan

[Q Man]

Thank you for the responses.

I have checked the jumpers and they are correct but my bridge resistance is 120 ohms so I will try the 3.33V setting and see what happens.

Thanks again for the input

Jason