Thermocouples

Cold junction compensation

The cold junction temperature is not measured in the box. For cold junction compensation, a Pt1000 measuring resistor must be connected in addition to the thermocouple. Place the Pt1000 measuring resistor as close as possible to the cold junction.

Recommendation: Use the ZS2000-3712 connector from Beckhoff instead of a separate Pt1000 measuring resistor. The ZS2000-3712 has an integrated Pt1000 measuring resistor that measures the temperature directly at the cold junction.

The highest accuracy can be achieved if a ZS2000-3712 or a Pt1000 measuring resistor is used for each connection. See Connection example 1
Alternatively, you can save costs by connecting a ZS2000-3712 or a Pt1000 measuring resistor to channel 1 only. In this case cold junction compensation of the other channels is carried out with the cold junction temperature of channel 1. See Connection example 2.

Extension cable

You can use an M12 extension cable between the box and the cold junction. However, this reduces the measuring accuracy. The longer the extension cable, the greater the measuring error.

The maximum permissible cable length between the box and the thermocouple is 30 m.