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Siemens
Desigo TRA Engineering, mounting and installation
CM111043en_09
Building Technologies
Wiring of field devices (without bus)
2016-02-22
Another limiting factor for cable length is
hum injection
for certain sensitive signal
types:
Signal type
Normal hum
Reduced hum
mA
eff
Can be maintained
with cable length
mA
eff
Can be maintained with
cable length / shield
TXM1.8U AI
NTC100K --
--
0.05
30 m / 100 ft (80 m with shield *)
AI NTC10K
--
--
0.05
30 m / 100 ft (80 m with shield *)
All other
signal types
0.5
300 m / 1000 ft
0.05 300 m / 10000 ft
DXR2...
AI NTC100K
--
--
0.05 30 m / 100 ft
(80 m / 260 ft with shield *)
AI NTC10K
--
--
0.05 30 m / 100 ft
(80 m / 260 ft with shield *)
AI NTC3K
--
--
0.05 30 m / 100 ft
(80 m / 260 ft with shield *)
AI R100K
--
--
0.05 30 m / 100 ft
(80 m / 260 ft with shield *)
All other
signal types
0.13 80 m / 260 ft
0.05 80 m / 260 ft
*) Connect the shield to system neutral on one end.
The measured value functions are already adjusted with a line resistance of 1 ohm
and the graphs below take account of this.
Exception: NTC3K, NTC10K and NTC100K.
The graphs below are for copper cable.
Measured value error due to line resistance
2
1
0
100
200
300
F [K]
L [m]
-0,21
1 mm
²
1,5 mm
²
2,5 mm
²
1
07
62
d0
34
0,6 mm Ø
Formula: F =
4.7
1
A
57
L
2
A
Cable cross-section in mm
2
F
Measured temperature error in K
L
Cable length in m
Hum injection
Line resistance
compensation
("Sensor calibration")
Measured value error
LG-Ni 1000
Key
