Siemens SITRANS T3K PA Instruction Manual page 86

7NG3213
Thermocouples
1)
3
4
--
Determining the comparative tem-
perature with built-in Pt100 or external
reference temperature
1) 3
4
--
Determining the comparative
temperature with external Pt100;
resistance programmable for line
compensation
3
1)
4
--
--
Difference/averaging circuit
with internal comparative temperature
The measured value is applied at logic channel 1. In difference and averaging circuit the
measured value calculation is determined by the measuring type (see above section
"Measuring type coding"). You can get the measured values of the single channels from the
secondary variables.
1)
Attention !
Fit short-circuit bridges on the system side on site.
Figure 5 Sensor pin assignment (continued)
86
2
1
+
TC
2
1
+
Pt100
2
1
+
TC1
+
TC2
Millivolt transmitter
1)
3
4
Two-wire circuit
without line compensation
Measuring type coding
R1, RTD1 or TC1 are used for determining
the secondary variable 1 (Channel 1). R2,
RTD2 or TC2 is used for measuring
secondary variable 2 (Channel 2).
Measuring Measured value
type calculation
Single
Channel 1
channel
Diff 1*) Channel 1 -- Channel 2
Channel 2 -- Channel 1
Diff 2)*)
1
/ × (Channel 1 + Channel 2)
Average 1*)
2
1
/ × (Channel 1 + Channel 2),
Average 2*)
2
in the case of an error as
equivalent value Channel 1 or
Channel 2
*) Diff = Difference circuit
Average = Averaging circuit
Instruction Manual
2
1
-- +
SITRANS T3K PA
C79000-B7174-C55-04