Using a compensating box
The effect of the temperature on the comparison point of a thermocouple (such as a terminal
box) can be adjusted with a compensating box.
The compensating box contains a bridge circuit that is adjusted for a certain comparison
point temperature (compensating temperature). You connect the thermocouples or their
compensating lines to the compensating box. The compensating box then forms the
If the actual reference temperature differs from the compensating temperature, the
temperature-dependent bridge resistance changes. A positive or negative compensation
voltage occurs; this is added to the thermo-electromotive force.
Compensating boxes with a comparison point temperature of 0°C must be used for the
compensation of the analog input modules.
● The power supply to the compensating box must be isolated.
● The power supply unit must have adequate interference filtering (by means of a grounded
Wiring unused channels on analog input modules
Pay attention to the following instructions when wiring unused channels:
● "Deactivate" unused input channels when assigning parameters.
● A deactivated channel always returns the value 7FFF
● The module cycle time is halved with the 2AI TC HF standard module.
● To adhere to the permissible potential differences (U
2AI TC HF
2AI TC HF analog electronic module (6ES7134-4NB01-0AB0)
Manual, 04/2007, A5E01076892-01
shielding winding, for example).
terminal module for the unused channels.
Analog input module
5.3 Wiring unused channels on analog input modules
), you must wire jumpers on the
TM connecting terminal