Calibration and PreScaled Values

[Eric Martell]

There have been similar questions asked so far, but I haven't seen someone with the same problems I have, so here goes:

I'm trying to calibrate two load cells from Cooper Instruments (100 lb, LFS 260-100).  They are connected to an SCC-SG24 in an SC-2345 box. 

If I look at the connection in MAX, it tells me that for both channels, the Mode is "On Demand", the Input Configuration is "NRSE", and the Max/Min Input Limits are +/- 100m.

The VI is a very simple one - the DAQ Assistant and two numerical outputs (in a while loop).  Each channel is set for an internal excitation source at 10 V (the Use Ex for Scaling box is checked), the scale is linear, and it's set at "Full Bridge".

When I run the Channel Calibration Wizard in the DAQ Assistant, I'm hanging a series of weights from the load cell and commiting the values for each. 

Now, here's the problem - if I only use one load cell, the calibration goes fine, and everything works as expected.  Using both load cells, however, it only works if I do a very minimalist calibration (values at the extreme ends of the range), but if I try to get a more accurate calibration by including more values during the calibration, I get Error 200939, saying

"The Channel Calibration Scale Pre-Scaled Values specified is not supported, because one of the numbers appears more than once in the specified array.  Ensure unique numbers are specified in the array.

Channel Name: CustVoltage0
Property: AI.ChanCal.Table.PreScaledVals
Repeated Value: 0.000000
TaskName: _unnamedTask<A>"

I've tried recalibrating, I've printed out the tables of values, and there's not any 0.000000's in there at all.  I'm very baffled.  Any help would be most welcome.

Thanks,

Eric Martell

[McKala[DE]]

Hello Eric,

This seems to be a bug in older versions of the NI-DAQmx driver, it was recently fixed in NI-DAQmx 8.3, which was released today and is available for download.

Let us know if you have any further questions or problems.