Siemens SIMATIC S7 System Manual page 757

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 configuration. 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- 123 Representation of analog values of thermocouples type J
Type J in °C
> 1450.0
1450.0
:
1200.1
1200.0
:
-150.0
-150.1
:
-210.0
< -210.0
Faulty wiring (for example, polarity reversal, or open inputs) or sensor error in the negative
1
range (for example, wrong type of thermocouple) may cause the thermocouple module to
signal underflow.
S7-200 SMART
System Manual, V2.3, 07/2017, A5E03822230-AF
Units
Decimal Hexadecimal
32767 7FFF
14500 38A4
: :
12001 2EE1
12000 2EE0
: :
-1500 FA24
-1501 FA23
: :
-2100 F7CC
-32768 8000
A.5 Thermocouple and RTD expansion modules (EMs)
Type J in °F
Decimal
> 2642.0 32767
2642.0 26420
: :
2192.2 21922
2192.0 21920
: :
-238.0 -2380
-238.2 -2382
: :
-346.0 -3460
< -346.0 -32768
Technical specifications
Units
Range
Hexadecimal
7FFF Overflow
6734 Overrange
:
55A2
55A0 Rated range
:
F6B4
F6B2 Underrange
:
F27C
8000 Underflow
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