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The Transducer Block
3.8 AI_TRANSDUCER Block (PA Slot 3) Parameter List
SITRANS TH400 PROFIBUS® PA
Configuration Manual, 02/2007, A5E01039143-01
29
3.8.3
Thermocouple specific parameters
Parameter
Rel.
Index
PA
Description
Type
Store Size
byte
RO /
R/W Min. Max. Default
RJ_TEMP
33
Reference junction temperature. The unit of RJ_TEMP is the
PRIMARY_VALUE_UNIT. If PRIMARY_VALUE_UNIT is no
temperature unit (e.g. mV) RJ_TEMP is stated in °C.
Float
D
4
RO
0
RJ_TYPE
34
Select reference junction from internal to fixed value. Ignored for
sensors which are not thermocouple types.
Defined codes:
0 = No reference:
Compensation is not used (e.g. for
TC type B).
1 = Internal:
Reference junction temperature is
measured by the device itself, via
an internally mounted sensor.
2 = External:
The fixed value EXTERNAL_RJ_
VALUE is used for compensation.
The reference junction must be kept
at a constant temperature (e.g. by a
reference junction thermostat).
3 = Sensor, 2-w.:
Reference junction temperature is
measured by external 2-wire con-
nected Pt100 sensor.
4 = Sensor, 3-w:
Reference junction temperature is
measured by external 3-wire con-
nected Pt100 sensor.
Unsigned
8
SRC
1
R/W
0
EXTERNAL_RJ_VALUE 35
Fixed temperature value of an external reference junction. The
unit of EXTERNAL_RJ_VALUE is the PRIMARY_VALUE_UNIT.
If PRIMARY_VALUE_UNIT is no temperature unit (e.g. mV)
EXTERNAL_RJ_VALUE is stated in °C.
Float
SRC 4
R/W
-40
(°C)
135
(°C)
0
RJ_COMP_WIRE
66
Value in OHM to compensate line resistance when External RJ
sensor, connected with 2 wires is used.
Float
SRC 4
R/W 0
100
0