Siemens SIMATIC PCS 7 - Page 194

Technical specifications
The accuracy of temperature measurement with internal
compensation (terminal temperature) results from:
● Error for the analog input of the type
of thermocouple used
● Accuracy
1
of the internal reference
junction temperature ± 2.5 K (in the
range 0 to 60 °C
1
Due to the increasing slope of the thermocouple characteristic curve at higher temperatures, the error
of the compensation element has less influence than at temperatures in the vicinity of the compensation
temperature. Exception: Thermocouple types J and E (relatively linear curve). In the case of thermo‐
couple type B, its negligible slope in the range from approximately 0°C to 40°C means that a missing
compensation of the reference junction temperature has only a slight effect. When compensation is
missing and "Compensation at 0°C" measurement type is set, the discrepancy in the case of thermo‐
couple type B for measurement temperatures between:
700°C and 1820°C is < 0.5°C
500 °C and 700 °C is < 0.7°C.
"Internal compensation" should be set if the reference junction temperature closely corresponds to the
module temperature. This reduces the error for the temperature range from 500 °C to 1820 °C to < 0.5
°C.
Error limits of analog inputs for thermocouples
(at 25
°
C ambient temperature and 100 ms integration time)
Type Temperature range Basic error
1
Temperature error
2
[°C/K]
T -150 °C...+400 °C
-230 °C... -150°C
± 0.2K
± 1K
± 0.006
U -50 °C....+400 °C
200 °C....-50 °C
± 0.2K
± 1K
± 0.006
E -100 °C....+1000 °C
-200 °C....-100 °C
± 0.2K
± 1K
± 0.0075
J -150 °C....+1200 °C
-210 °C ... -150 °C
± 0.2K
± 0.5K
± 0.02
L -50 °C....+1200 °C
-200 °C....-50 °C
± 0.2K
± 1K
± 0.02
K -100 °C....+1372 °C
220 °C....-100 °C
± 0.2K
± 1K
± 0.018
N -50 °C....+1300 °C
150 °C....-50 °C
± 0.2K
± 1K
± 0.025
R +200 °C....+1769 °C
-50 °C....+200 °C
± 0.3K
± 1K
± 0.025
S +100 °C....+1769 °C
-50 °C....+100 °C
± 0.3K
± 1K
± 0.025
B +700 °C....+1820 °C
+500 °C....+700 °C
+200 °C....+500 °C
± 0.3K
± 0.5K
± 3K
± 0.04
ET 200PA SMART I/O modules
10.4 Analog input modules
ET 200PA SMART
194 Operating Instructions, 06/2019, A5E34192013-AB