Siemens SIMATIC ET 200AL, System Manual

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Parameters/address space
4.3 Explanation of the parameters
Analog input module AI 4xRTD/TC 4xM12 (6ES7144-5KD50-0BA0)
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Equipment Manual, 08/2021, A5E48753535-AB
Compensation
type
Explanation
Internal reference
junction
Properties
With this compensation type, the reference junction temperature is determined with an internal tem-
perature sensor that is integrated in the AI 4xRTD/TC 4xM12 electronic module.
Note: Take the reaction time to changes of the ambient temperature into account.
Principle of operation
The reference junction temperature is detected through an internal temperature sensor.
All channels of the AI 4xRTD/TC 4xM12 that you select for this type of compensation receive the same
reference junction temperature.
Wiring
Connect the thermocouples directly or with compensating lines to the AI 4xRTD/TC 4xM12.
No compensation Properties
With this compensation type, the reference junction temperature of the thermocouples is measured
outside the AI 4xRTD/TC 4xM12 electronic module. You can, for example, connect a compensating box
to the thermocouple for this purpose.
Principle of operation
The temperature of the reference junction for this type of compensation is specified as 0 °C.
This can be achieved by using a compensating box. A separate compensating box is required for each
thermocouple.
Wiring
Connect the compensating box with theAI 4xRTD/TC 4xM12 with copper cables.
Note: Thermocouples of Type B do not require a compensating box up to a reference junction temper-
ature of 50 °C.