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7 Start-Up
System Manual Modular Systems
Page 52 of 114
HI 800 191 E Rev. 2.02
2. Use a clamp to connect the shielding of a cable (if present) to the earth grid. To this end,
place the clamp over the surface of the stripped cable shielding and press it from both sides
into the oblong holes of the earth grid until it snaps into position.
The cables are attached and the shielding is connected.
Cable shielding
Shield clamp
Cable straps
Figure 10: Securing the Cables and Connecting the Shielding
NOTE
Cable failure is possible under tensile load!
Do not use the shield clamp as a strain relief for the connected cable!
7.2.6
Earthing and Shielding
7.2.6.1
Earthing the 24 VDC System Voltage
All devices of the HIMatrix family must be operated with power supply units that comply with the
SELV (Safety Extra Low Voltage) or PELV (Protective Extra Low Voltage) requirements. A
functional earth is prescribed to improve the electromagnetic compatibility (EMC).
All HIMatrix systems can be operated with earthed L- or unearthed.
Unearthed Operation
Unearthed operation offers some advantages in terms of EMC behavior.
Some applications have specific requirements for the unearthed operation of controllers, e.g., in
accordance with the VDE 0116/EN 50126 standard, earth fault monitoring is required for
unearthed operation.
Earthed Operation
The earth must be designed in accordance with the standard and must have a separate earth
contact through which no power-dependent interference current may flow. Only earthing of
negative pole (L-) is permitted. Earthing of positive pole (L+) is not permitted since a potential
earth fault on the transmitter line would bypass the affected transmitter.
L- can only be earthed on one place within the system. L- is usually earthed directly behind the
power supply unit, e.g., on the busbar. The earthing should be easily accessible and well
separable. The earthing resistance must be ≤ 2
.