Load Cell Scaling Issues NI9237 / cDAQ9178

[ChrisDavies]

Hi All,

I am currently using a DAQ 9178 with a NI 9237 module to measure a load cell input. (Labview version 2012 SP1)

I get an output on the graph, but only as a hex code!

I have the load cell (Omni Instruments DBBSE - 250 kg) configured as follows -

Full bridge / Internal Vex source / 10 V for Vex value / Bridge resistance 350 and scale as 0 - 10 mv / V.

Any help would be greatly appreciated as I'm new to this development malarkey!!!

Thanks,

Chris

[Sinead_Brady_NIUK]

Hi Chris,

I am attaching a few examples and knowledge based articles that you may find helpful:

1) How Do I Configure a Load Cell in MAX with the NI 9237?
This knowledge based article explains how to configure your load cell with the NI 9237 in National Instruments Measurement and Automation Explorer.

2) Load Cell Data Acquisition Reference Example with Null Offset and Shunt Calibration

This example gives sample code on how to acquire load cell data, along with null offset and shunt calibration if you require this. This code uses DAQmx functions which are lower level functions that work in the same way as the DAQ Express VI that you used. The following White Paper explains how the most common DAQmx functions work.

Learn 10 Functions in NI-DAQmx and Handle 80 Percent of Your Data Acquisition Applications

If you have any other questions, please let me know,

Regards, 

[ChrisDavies]

Hi Sinead,

Thanks for the reply.

I've tried running that load_cell_null_off_shuntcal VI and it does read a value on my configuration, but there appears to be a scaling issue.

The load cell I am using is 250 Kg, so I changed that from Ibs to Kgs. The excitation value I am using is 10 Volts and I've set the mV/V value to 1.

I feel like there I'm nearly there but I'm just trying to config the scaling.....

Any help would be greatly appreciated!

Thanks,

Chris

[Sinead_Brady_NIUK]

Dear Chris,

Sorry for the delayed response. Have you been able to solve your problem? If not can you please attach your updated VI with the corrections for calibration, so I can have a better idea as to where the issue maybe occuring?

Regards, 

[ChrisDavies]

Hi Sinead,

Sorry for the late response, here is the updated VI as requested.

Thanks,

Chris

[Sinead_Brady_NIUK]

Dear Chris, 

How much is the scaling now out by?

Kind Regards,