Siemens ET 200pro Operating Instructions Manual page 431

Compensation Explanation
type
RTD (0) Properties
The compensation is based on a measurement of the resistance value of a Pt1000 at the contact
point of the M12 compensation connector or an external resistance value Pt1000. The resistance
measurement is only possible at the circular socket X1 (channel 0).
Principle of operation
The temperature at the reference junction can be determined from the Pt1000 resistance value.
All the 4 AI TC High Feature channels you select for this compensation type obtain the same
reference junction temperature.
Connection
•
•
Additional thermocouples can be connected to circular socket connectors X2 to X4 on the
CM IO 4 x M12 of the 4 AI TC High Feature. The reference junction temperature recorded by
measuring the resistance value at circular socket connector X1 applies to all the module's channels
you have selected for this compensation type (see the example in the Appendix, Connecting
thermocouples to analog inputs (Page 520)).
ET 200pro distributed I/O system
Operating Instructions, 03/2013, A5E00335544-08
With an M12 compensation connector:
Connect the thermocouple to the M12 compensation connector either directly or using
compensating lines. Fit the M12 compensation connector onto circular socket connector X1
(channel 0) of the CM IO 4 x M12 on the 4 AI TC High Feature.
Without an M12 compensation connector:
– Connect an external Pt1000 (where α = 0.03851) to terminals 1 and 3 using copper cables to
record the reference junction temperature. The Pt1000 thermal resistor must be positioned
near the reference junction.
– Connect the thermocouples to terminals 2 and 4 using copper cables from the reference
junction.
15.8 Overview of parameters of the analog electronic modules
Analog electronic modules
431