Connection of Resistance Thermometers in 2-wire Configuration to the \ Analog Inputs

When resistance thermometers (Pt100, Pt1000, Ni1000) are used, a constant current must flow to build the necessary voltage drop for the evaluation. For this, the module CI581-CN provides a constant current source which is multiplexed over the max. 4 analog input channels.

The following figure shows the connection of resistance thermometers in 2-wire configuration to the analog input AI0. Proceed with the analog inputs AI1 to AI3 in the same way.

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Connection of resistance thermometers in 2-wire configuration to the analog inputs

Pt100 2-wire configuration, 1 channel used
Pt1000 2-wire configuration, 1 channel used
Ni1000 2-wire configuration, 1 channel used

For the measuring ranges that can be configured, please refer to sections Measuring Ranges CI581-CN and Parameterization CI581-CN.

The module CI581-CN performs a linearization of the resistance characteristic.

To avoid error messages, configure unused analog input channels as “unused”.