User Manual
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Siemens TX-I/O Engineering and installation guide CM110562en_13
Building Technologies Principles of electrical design 2019-05-15
4) The range monitoring of signal type U10 is done with a short NEGATIVE signal of
–3,1 V, 0.05 mA (open circuit detection). If a field device has an open output, a
negative voltage could appear there. This can damage any polarized components
(e.g. capacitors).
5) When the process value is outside the range, a fault message is issued.
6) AI PT1K375: Restriction for hum injection only for TXM1.8P.
No restriction for TXM1.8U und TXM1.8X.
"Reduced
hum injection"
Signal type Normal hum Reduced hum
mA
eff
Cable
length
Temperature mA
eff
Cable
length
Temperature
TXM1.8U…, TXM1.8X…
AI Ni1000
0.5
300 m
-50 … 150 °C
--
--
--
AI Ni1000
extended
0.5 300 m -50 … 150 °C 0.3 180 m 150 … 180 °C
AI T1 (PTC)
0.5
300 m
-50 … 130 °C
0.4
240 m
130 … 150 °C
AI PT1K385
0.5
300 m
-50 … 400 °C
0.25
150 m
400 ... 600 °C
AI PT1K375
0.5
300 m
-50 … 180 °C
--
--
--
AI NTC100K
--
--
--
0.05
30 m
-40 ... 115 °C
AI NTC10K
--
--
--
0.05
30 m
-40 ... 125 °C
TXM1.8P
AI Ni1000
0.5
300 m
-50 … 150 °C
--
--
--
AI Ni1000
extended
0.5 300 m -50 … 150 °C 0.3 180 m 150 … 180 °C
AI PT1K385
0.5
300 m
-50 … 400 °C
0.2
120 m
400 ... 600 °C
AI PT1K375
0.5
300 m
-50 … 150 °C
0.4
240 m
150 … 180 °C
AI Pt100
4 wire
0.5 300 m -50 … 400 °C 0.1 60 m 400 ... 600 °C
To realize the specified measuring accuracy, 0.5 mA of hum are admissible.
This hum is typically caused by a mains AC 230 V cable routed in the same cable duct
as the measuring cable over a length of 300 m (cable lengths over 300 m are unfavo-
rable for other reasons).
To measure temperatures over 150 °C accurately, the hum must be reduced to 0.3 mA.
This can be achieved
– by reducing the length to 180 m
– by routing the measuring cable and the hum source in separate cable ducts
– by a shielded cable (connect the shield to system neutral ⊥ on one end).
NTC sensors are measured with a very small measuring current. To realize the
specified measuring accuracy, only 0.05 mA of hum is admissible.
This hum is typically caused by a mains AC 230 V cable routed in the same cable duct
as the measuring cable over a length of 30 m.
Measuring cables longer than 30 m must be shielded (connect the shield to system
neutral ⊥ on one end).
Caution!
Example
s:
AI Ni1000 extended
AI NTC10K