tion points, remove the lacquer so that there is safe electrical contact over a
large surface area. You achieve contact over a large surface area by means of
bare connection surfaces or several connection screws. For screw connections,
you can establish the contact to lacquered surfaces by using tooth lock wash-
ers.
Metal Surfaces
Always use connection elements (screws, nuts, plain washers) with good elec-
troconductive surface.
Bare zinc-coated or tinned metal surfaces have good electroconductive proper-
ties.
Anodized, yellow chromatized, black gunmetal finish or lacquered metal surfa-
ces have bad electroconductive properties.
Ground Wires and Shield Connections
For connecting ground wires and shield connections, it is not the cross section
but the size of contact surface that is important, as the high-frequency interfer-
ence current mainly flow on the surface of the conductor.
11.3.8 Installing Signal Lines and Signal Cables
Line Routing
The following measures are recommend:
● Route signal and control lines separately from the power cables with a mini-
mum distance of d5=100 mm (see "Division into Areas (zones)" on page 0 )
or with a grounded separating sheet. The optimum way is to route them in
separate cable ducts. If possible, lead signal lines into the control cabinet at
one point only.
● If signal lines are crossing power cables, route them in an angle of 90° in or-
der to avoid interference injection.
● Ground spare cables, that are not used and have been connected, at least at
both ends so that they do not have any antenna effect.
● Avoid unnecessary line lengths.
● Run cables as close as possible to grounded metal surfaces (reference poten-
tial). The ideal solution are closed, grounded cable ducts or metal pipes
which, however, is only obligatory for high requirements (sensitive instrument
leads).
● Avoid suspended lines or lines routed along synthetic carries, because they
are functioning like reception antennas (noise immunity) and like transmitting
antennas (emission of interference). Exceptional cases are flexible cable
tracks over short distances of a maximum of 5 m.
Shielding
Connect the cable shield immediately at the devices in the shortest and most di-
rect possible way and over the largest possible surface area.
Bosch Rexroth AG
Electromagnetic Compatibility (EMC)
EFC 3600
158/259
DOK-RCON03-EFC-3600***-IT03-EN-P
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