Siemens Simatic S7 Series

Technical specifications
A.5 Thermocouple and RTD expansion modules (EMs)
S7-200 SMART
System Manual, 09/2015, A5E03822230-AC
631
It is recommended for measuring thermocouples that a 100 ms integration time be used. The
use of smaller integration times will increase the repeatability error of the temperature
readings.
Note
After power is applied, the module performs internal calibration for the analog
-to-digital
converter. During this time the module reports a value of 32767 on each channel
until valid
data is available on that channel. Your user program may need to allow for this initialization
time. Because the configuration of the module can vary the length of the initialization time,
you should verify the behavior of the module in your c
onfiguration. If required, you can
include logic in your user program to accommodate the initialization time of the module.
Representation of analog values for Thermocouple Type J
A representation of the analog values of thermocouples type J is shown in the table below.
Table A- 115 Representation of analog values of thermocouples type J
Type J in °C
Units
Type J in °F
Units
Range
Decimal
Hexadecimal
Decimal
Hexadecimal
> 1450.0
32767
7FFF
> 2642.0
32767
7FFF
Overflow
1450.0
:
1200.1
14500
:
12001
38A4
:
2EE1
2642.0
:
2192.2
26420
:
21922
6734
:
55A2
Overrange
1200.0
:
-150.0
12000
:
-1500
2EE0
:
FA24
2192.0
:
-238.0
21920
:
-2380
55A0
:
F6B4
Rated range
-150.1
:
-210.0
-1501
:
-2100
FA23
:
F7CC
-238.2
:
-346.0
-2382
:
-3460
F6B2
:
F27C
Underrange
< -210.0
-32768
8000
< -346.0
-32768
8000
Underflow
1
1
Faulty wiring (for example, polarity reversal, or open inputs) or sensor error in the negative
range (for example, wrong type of thermocouple) may cause the thermocouple module to
signal underflow.