Eaton XN300 - Page 196

26 Analog input module XN-322-10AI-TEKT
26.2 Wiring topic
XN300 slice modules 02/24 MN050002EN Eaton.com 192
provided there are no localized temperature differences (X5 vs. X1). If this
type of temperature difference exists, as is the case when a system has
specific sides warm up in a localized manner during operation, it will affect
the measurement in the form of an error.
In order to isolate the measurement from the system assembly's local
conditions, as well as to compensate for large distances, it is possible to use
wheatstone bridge compensation circuits in which the thermocouples are
wired in a thermally stable environment, as is the measurement of the cold
junction temperature with the KTY sensor.
Figure 106: Wiring example with 4 thermocouples on an external KTY sensor; the 
M
measuring points and the 
Ref1
and 
Ref2
reference junctions are clearly shown

X1
1+ 1- 2+ 2- 4-
X2
3+ 3- 4+
X3 X4 X5
K+ K- K+ K-
PE
24 V
0 V
8-7+ 7- 8+6-5+ 5- 6+
ϑ
Ref1
ϑ
Ref1
ϑ
Ref2
ϑ
Ref2
+ -
ϑ
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+ -
ϑ
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+ -
ϑ
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+ -
ϑ
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+ -
ϑ
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+ -
ϑ
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+ -
ϑ
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+ -
ϑ
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