Installing Signal Lines And Signal Cables; General Measures Of Radio Interference Suppression For Relays, Contactors, Switches, Chokes And Inductive Loads - Bosch Rexroth IndraDrive HMS02 Instruction Manual

DOK-INDRV*-HMS02*UL***-IB03-EN-P
Rexroth IndraDrive Drive Controllers Power Sections HMS02
Ground Wires and Shield Connec‐
6.4

Installing Signal Lines and Signal Cables

Line Routing
Shielding
6.5 General Measures of Radio Interference Suppression for Re‐
lays, Contactors, Switches, Chokes and Inductive Loads
Anodized, yellow chromatized, black gunmetal finish or lacquered metal surfa‐
ces have bad electroconductive properties.
For connecting ground wires and shield connections, it is not the cross section
tions
but the size of contact surface that is important, as the high-frequency interfer‐
ence currents mainly flow on the surface of the conductor.
Always connect cable shields, especially shields of the motor power cables, to
ground potential over a large surface area.
For measures to prevent interference, see the Project Planning Manuals of the
respective device. In addition, we recommend the following measures:
● Route signal and control lines separately from the power cables with a
minimum distance of d5 = 100 mm (see
(Zones), page
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
order 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
potential). 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 carriers, 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.
Connect the cable shield immediately at the devices in the shortest and most
direct possible way and over the largest possible surface area.
Connect the shield of analog signal lines at one end over a large surface area,
normally in the control cabinet at the analog device. Make sure the connection
to ground/housing is short and over a large surface area.
Connect the shield of digital signal lines at both ends over a large surface area
and in short form. In the case of potential differences between beginning and
end of the line, run an additional bonding conductor in parallel. This prevents
compensating current from flowing via the shield. The guide value for the cross
section is 10 mm 2 .
You absolutely have to equip separable connections with connectors with
grounded metal housing.
In the case of non-shielded lines belonging to the same circuit, twist feeder and
return cable.
If, in conjunction with electronic devices and components, inductive loads, such
as chokes, contactors, relays are switched by contacts or semiconductors, ap‐
propriate interference suppression has to be provided for them:
● By arranging free-wheeling diodes in the case of d.c. operation
EMC Measures for Design and Installation
46) or with a grounded separating sheet. The optimum way
Bosch Rexroth AG 55/67
6.2.2 Division Into Areas