Excitation

Each differential channel has an excitation terminal labeled EX. This terminal can be used as either a calibrated excitation for a resistive bridge measurement or as a general voltage source for powering an amplified sensor. Each excitation terminal has four settings:

1. Off. The terminal stays in a high-impedance state

2. 5 V. This is a constant voltage source set to 5 V. The excitation can source up to 100 mA at this voltage

3. 10 V. This is a constant voltage source set to 10 V. The excitation can source up to 100 mA at this voltage

4. 10 mA. This is a constant current source set to 10 mA. The excitation can rise to as much as 12 V while maintaining this current

The absolute accuracy of an excitation voltage or current should be considered differently depending on whether it is being used in a bridge measurement or as an independent power source. When used as an independent power source, the accuracy given in the specification table applies.

When the excitation is used to power a bridge sensor, the CRBasic instruction CDM_BridgeFilt() should be used. When excitation is used with this instruction, excitation error is canceled out due to the internal ratiometric relationship between the excitation and the input measurement. Excitation error is also corrected with internal calibration over the full temperature range. Thus, the excitation accuracy error can be ignored and should not be added to the input measurement accuracy error to compute total error. Instead, refer only to the specified input measurement accuracy when performing bridge measurements.