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Tech Support > Tutorials: Calibrating an SGA01

Calibrating an SGA01 with a Dataq DI-154RS or DI-194RS

A complete calibration of the signal chain includes calibrating the sensor, amplifier, and ADC. The best way to do this is via the ADC software which will calibrate the complete signal chain. The instructions given below are for the Dataq WinDaq Lite software available for free from www.dataq.com.

First open WinDaq Lite. The default oscilloscope screen looks like this:

It's easier to work with if you only display one channel. To display one channel click View - Format Screen- 1 Waveform as shown below:

A standard Dataq module is setup for +/- 10V input voltage range, however we are only using 0 to 10V, i.e. 0 to 44lbf.  We have to modify the display so that this is taken into account. To do this click Edit - Fixed Calibration. The default screen looks like this:

Enter 44 in the High Calibrator entry, -44 in the Low Calibrator entry, and lbf in Engr. Units. Click OK.

Now we have to actually calibrate the system using a two point calibration.  The two points will be zero and a known weight. I use a 10lb Toledo scale weight as the known weight, but you can also use a measured gallon (8 lbf), or two (16lbf), or five (40lbf) of water as a known weight.

First, with no weight on the load cell, click Edit - Low Calibration:

Enter 0 for Low Cal Value and click OK:

Now put the known weight on the load cell. Click Edit - High Calibration.

Enter your known weight (in my case 10) for High Cal Value and click OK:

Now, with the weight removed, the waveform display should look like this:

Now we can clean up the display a bit. Since we only want to display positive values we can rescale the display for positive values only. Click Scaling - Limits.

Enter 0 in Bottom Limit:

Now the display looks like this with the known weight back on the load cell:

By the way, the "10.000 lbf"at center left is the value of the waveform at the marker, not the center of the scale.

To save all of this set up click File - Save Default Setup. Otherwise you will have to redo it every time you restart Windaq.

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