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Wiring Notes; Permissible Line Length And Cross-Sectional Areas - Siemens OpenAir GEB 1 Series Technical Basics

Actuators without spring return
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Permissible voltage drop
Notes on the G0 line
Building Technologies

Wiring notes

Prior to wiring, study all information in the following sections:
"Safety notes" in chapter 4.1
"Device-specific regulations" in chapter 4.2
"Notes on EMC optimization" in chapter 4.3
"Diagrams" in chapter 9, and the
HVAC plant diagram.
Permissible line length and cross-sectional
The line lengths and cross-sectional areas depend on the actuators power consumption
and the permissible voltage drop of the connection lines to the actuators. Determine the
necessary line length from the following diagram and the formulas.
To determine the line length and cross section, adhere to the permissible operating
voltage tolerance at the actuator (see chapter 8, "Technical data") in addition to the
permissible voltage drop between the signal and supply lines (see table below).
The line sizing between the controller and the actuators depends on the actuator type
used and is determined on the following basis.
Operating voltage
AC 24 V
AC 24 V
AC 230 V
Consider the following criteria:
For modulating control:
The permissible positioning signal error caused by a voltage drop in the line current
on the G0 line must not exceed 1%.
The G0 line's voltage drop caused by surges in the DC circuit in the actuator may
not exceed 2 Vpp.
In the case of improper sizing of the G0 line, actuator load changes may cause
natural oscillation due to a change in the DC voltage drop.
The supply voltage loss at AC 24 V may not exceed 8% (4% over G0 line).
DC voltage drop over the G0 line is caused as follows:
Asymmetrically in the internal actuator supply (ca. DC 8 mA).
Positioning signal current DC 0.1 mA (from Y = DC 10...10 V).
Positioning signal current DC 1 mA (from U = DC 0...10 V).
It can be ignored for the following aspects.
Technische Grundlagen: Drehantriebe GEB...1
Max. permissible voltage drop
G, Y1, Y2
4 % each (tot. 8 %) of AC 24 V
G0, G
4 % each (tot. 8 %) of AC 24 V
G0, Y, U
1 % of DC 10 V
L, N
2 % each (tot. 4 %) of AC 230V



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