3.2 - Differential analog inputs | LabJack
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3.2 - Differential analog inputs

Some devices support differential inputs.  To do differential, put the channel number for the negative side of the input in the Quick Note / Special / OPC column.

The U3 has a "special" range of 0-3.6 volts for a low-voltage channel or -10 to +20 volts for a high-voltage channel.  This range is not specified with typical range commands in script, but rather by specifying a differential read where the negative channel is 32.  This is a signal to the UD driver to use the special range, so put channel number 32 in the Quick Note / Special / OPC column.  The result is not a differential reading, but a single-ended reading with the special range.

Sample file: LJGuideSamples\InputsSimpleU3Diff.ctl