Wieland ricos FLEX BC MODBUS User Manual page 22

Proof the correct fixing of the lead isolation.
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In special use cases you should appoint special EMC actions.
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Create a homogeneous reference potential and ground all electrical operating supplies when possi-
ble
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Isolation of conductors
Electrical, magnetically and electromagnetic interference fields are weakened by means of an isola-
tion, one talks of absorption. Via the isolation rail, that is connected conductive with the rack, inter-
ference currents are shunt via cable isolation to the ground. Here you have to make sure, that the
connection to the protected earth conductor is impedance low, because otherwise the interference
currents may appear as interference cause.
When isolating cables you have to regard the following:
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Please regard at installation: At potential differences between the grounding points, there may be a
compensation current via the isolation connected at both sides.
Remedy: Potential compensation line
CAUTION
Wieland Electric GmbH | BA001269 | 09/2021 (Rev. A)
Data lines must be laid isolated.
Analog lines must be laid isolated. When transmitting signals with small amplitudes the
one-sided laying of the isolation may be favorable.
Lay the line isolation extensively on an isolation/protected earth conductor rail directly af-
ter the cabinet entry and fix the isolation with cable clamps.
Make sure that the isolation/protected earth conductor rail is connected impedance-low
with the cabinet.
Use metallic or metallized plug cases for isolated data lines.
Consider to wire all inductivities with erase links.
Please consider luminescent lamps can influence signal lines.
Please take care for the targeted employment of the grounding actions. The grounding of
the PLC serves for protection and functionality activity.
Connect installation parts and cabinets with your PLC in star topology with the isola-
tion/protected earth conductor system. So you avoid ground loops.
If there are potential differences between installation parts and cabinets, lay sufficiently
dimensioned potential compensation lines.
If possible, use only cables with isolation tangle.
The hiding power of the isolation should be higher than 80%.
Normally you should always lay the isolation of cables on both sides. Only by means of the
both-sided connection of the isolation you achieve high quality interference suppression in
the higher frequency area. Only as exception you may also lay the isolation one-sided.
Then you only achieve the absorption of the lower frequencies. A one-sided isolation con-
nection may be convenient, if:
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the conduction of a potential compensating line is not possible.
o analog signals (some mV respectively μA) are transferred.
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foil isolations (static isolations) are used.
With data lines always use metallic or metallized plugs for serial couplings. Fix the isolation
of the data line at the plug rack. Do not lay the isolation on the PIN 1 of the plug bar!
At stationary operation it is convenient to strip the insulated cable interruption free and lay
it on the isolation/protected earth conductor line.
To fix the isolation tangles use cable clamps out of metal. The clamps must clasp the isola-
tion extensively and have well contact.
Lay the isolation on an isolation rail directly after the entry of the cable in the cabinet. Lead
the isolation further on to your PLC and do not lay it on there again!
Mounting, wiring and demounting
22