3RH, 3TX, LZX coupling links
SIRIUS System Manual
6-10
GWA 4NEB 430 0999-02b
6.3 Application and areas of use
6.3.1 General information
Advantages
The use of coupling links offers the following advantages:
• Galvanic isolation between two circuits
• Current gain
• Protects the controller from interference and overvoltage
• Substantially reduces the power input of switchgear
• Permits power gain or level adaptation
Applications
Coupling links are used in:
• Production engineering
• Machine setup
• Process control in power distribution
• Building services automation
• Process engineering
Usage
Coupling links are used for:
• Floating signal transmission
• Linking of different voltages (AC/DC) and currents
• Power gain
• Level adaptation
• Protection of the controller against EMC noise from the I/O
• Contact multiplication
Application example
Figure 6-3: Application example, coupling links in box terminal format
6.3.2 Criteria for selection
Coupling links are selected on the basis of a number of criteria:
Technical specifications
See Section 6.7:
• Rated control supply voltage U
s
• Typical power input
• Output elements
• Rated operational currents I
e
• Permissible line length
M
110 VAC
230 VAC
24 VDC 24 VDC
110 VAC
230 VAC
Final control-
ling element
Electronic
controller
I/O
Devices
In-
put
Out-
put
Pushbutton
Position
switch
Coupling
link
Coup-
ling
link
Motor
contactor
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