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Introduction
Permissible cable
lengths and cross-
sectional areas
Note
Permissible voltage drop
Note on G0 line
(G..B181.1E/3 and
ASV181.1E/3)
20 / 42
Siemens
Building Technologies
4.2
Electrical installation / cabling
Prior to wiring, observe all information in the following sections:
„Safety notes" in section 7.1
„Device-specific regulation" in section 7.2.
„Notes on EMC optimization" in section 7.3.
4.2.1
Power supply cabling
The permissible cable lengths and cross-sectional areas depend on the VAV
compact controllers' current draw and the voltage drop on the connecting lines to
the actuators. The necessary cable lengths can be determined from the L/P chart
(next page) or with the help of the formulas. Cf. also technical data in section 8.
When determining the cable length and the cross-sectional area, it is to ensure that
the permissible tolerances of the VAV compact controllers' operating voltage are
adhered to, in addition to the permissible voltage drop on the power supply and
signal lines (table below).
The cables are to be sized depending on the type of VAV compact controller used
and based on the following data:
Type
G..B181.1E/3, ASV181.1E/3
The following criteria are to be considered:
For modulating control:
The permissible positioning signal error, caused by the voltage drop on the
G0 line, must not exceed 1 %
The voltage drop on the G0 line, caused by surges in the actuator's
rectifier circuit, must not exceed 2 Vpp
If the G0 line is not correctly sized, actuator load changes can produce
oscillations caused by changes in the DC voltage drop.
The supply voltage loss at AC 24 V must not exceed 8 % (4 % over the G0
line)
The DC voltage drop on the G0 line is caused by:
- Unsymmetry in the internal actuator power supply (> DC 8 mA)
- Positioning signal current DC 0.1 mA (from Y = DC 0...10 V) and
- Output signal current DC 1 mA (from U = DC 0...10 V).
The DC voltage drop can be ignored for the following considerations.
VAV compact controller G..B181.1E/3 | VAV modular controller ASV181.1E/3
Operating
Line
voltage
AC 24 V
G0, G
Max. permissible
voltage drop
each 4 % (tot. 8 %)
CE1P3544en
2016-02-26
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