Siemens ET 200pro Operating Instructions Manual page 432

Analog electronic modules
15.8 Overview of parameters of the analog electronic modules
Compensation Explanation
type
Dynamic ref. temp. Properties
With this form of compensation, the reference junction temperature can be measured using an
external module on another station.
Principle of operation
The temperature at the reference junction is communicated to the 4 AI TC High Feature electronic
module by data record DS2 from the CPU using SFB 53.
Each channel you select for this compensation type can be assigned its own reference junction
temperature via the user program. For more information, please refer to the section titled Dynamic
reference temperature for the 4 AI TC High Feature electronic module (Page 433).
Connection
Connect the thermocouples to terminals 2 and 4 using copper cables from the reference junction.
If you record the reference junction temperature directly at the M12 connector on the CM IO 4 x M12
of the 4 AI TC High Feature, you will also be able to connect the thermocouples either directly or
using compensating lines (see the example in the Appendix, Connecting thermocouples to analog
inputs (Page 520)).
Fixed ref. temp. Properties
With this compensation type, the reference junction temperature is stored as a fixed value.
Principle of operation
The temperature at the reference junction is defined in the "Reference temperature" parameter.
The table titled
Parameter overview for analog electronic modules (Page 419) shows the possible value range.
The reference junction temperature which has been programmed applies to all the module channels
you have selected for this compensation type.
Connection
Connect the thermocouples to terminals 2 and 4 using copper cables from the reference junction.
If you record the reference junction temperature directly at the M12 connector on the CM IO 4 x M12
of the 4 AI TC High Feature, you will also be able to connect the thermocouples either directly or
using compensating lines (see the example in the Appendix, Connecting thermocouples to analog
inputs (Page 520)).
Note
If a type B thermocouple or the ±80 mV measuring method is being used, "No" temperature
compensation will be performed regardless of the temperature compensation parameter
assignment.
432
"Reference temperature" parameter for 4 AI TC High Feature
in the section titled
ET 200pro distributed I/O system
Operating Instructions, 03/2013, A5E00335544-08