II - DCE FEL ČVUT v Praze

Temperature range
type N
I/O Modules with Intrinsically-Safe Signals
C79000-G7076-C152-04
Table 3-16 shows the representation of the digitized measured value for the
temperature range, sensor type N.
Table 3-16 Representation of the digitized measured value of an analog input
module (temperature range, type N)
Temperature
range in C
SIMATIC S7 Ex Analog Modules
Decimal Hexadecimal Range
> 1550.0 32767 7FFFH Overflow
1550.0
15500 3C8CH
:
:
:
Overrange
1300.1
13001 32C9H
2)
1300.0
:
:
-220.0 1)
13000 32C8H
:
:
:
-2200
:
F768H
Rated range
:
:
:
-270.0
-2700 F574H
-270.1 -2701 F573H Underrange 2)
In the case of incorrect wiring (e.g. polarity reversal, open inputs) or a sensor fault in
the negative range (e.g. incorrect type of thermocouple), ondropping below F0C4H
the analog input module signals underflow and outputs 8000H.
1) The module linearizes the range from +1300 to -220C for type N. Below -220C,
the rise of the characteristic curve decreases to such an extent that, from this point,
precision evaluation is no longer possible. The rise in the characteristic curve at this
point is retained until underrange is reached.
2) The characteristic of the thermocouple is not defined in the overrange and
underrange. The rise of the characteristic curve is retained on leaving the rated range.
It is not possible to specify the accuracy of these ranges.
3-17