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Siemens
Desigo TRA Engineering, mounting and installation
CM111043en_09
Building Technologies
Wiring of field devices (without bus)
2016-02-22
These devices have an internal rectifier, to convert AC 24 V to DC 24 V. This
causes a DC current to flow in the system neutral conductor ( ) which causes a
voltage drop over the line resistance. This voltage drop falsifies the DC 0...10 V
signal value.
The cable length must be reduced to limit the signal error (0.5% for sensors,
1% for actuators).
Cable cross section
Cable length
Power
1 VA
2 VA
5 VA
10 VA
20 VA
2.50 mm
2
/
AWG14
140 m
460 ft
70 m
230 ft
30 m
90 ft
15 m
45 ft
8 m
25 ft
1.50 mm
2
/
AWG16
90 m
290 ft
45 m
145 ft
20 m
60 ft
10 m
30 ft
5 m
15 ft
1.00 mm
2
/
AWG18
55 m
180 ft
30 m
90 ft
12 m
35 ft
6 m
20 ft
3 m
10 ft
0.75 mm
2
/
AWG20
35 m
110 ft
17 m
55 ft
7 m
25 ft
3 m
12 ft
2 m
6 ft
Cable cross section
Cable length
Power
1 VA
2 VA
5 VA
10 VA
20 VA
2.50 mm
2
/
AWG14
280 m
920 ft
140 m
460 ft
60 m
200 ft
30 m
90 ft
15 m
45 ft
1.50 mm
2
/
AWG16
180 m
580 ft
90 m
290 ft
40 m
120 ft
20 m
60 ft
10 m
30 ft
1.00 mm
2
/
AWG18
110 m
360 ft
55 m
180 ft
20 m
70 ft
12 m
35 ft
6 m
20 ft
0.75 mm
2
/
AWG20
70 m
220 ft
35 m
110 ft
15 m
50 ft
7 m
25 ft
3 m
12 ft
The outgoing and return cables may each have the indicated length.
Cable length for
devices with
AC/DC 24 V
Sensors
Actuators
Note
