REXROTH Fv Series, Инструкция по эксплуатации

Страница: 162 / 222

● 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 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
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 con‐
nection 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 pre‐
vents compensating current from flowing via the shield. The guide value for
the cross section is 10 mm2.
You absolutely have to equip separate connections with connectors with
grounded metal housing.
In the case of non-shielded lines belongs to the same circuit, twist feeder and
return cable.
General measures of radio interference suppression for relays, contactors, switches, chokes
and inductive loads
If, in conjunction with electronic devices and components, inductive loads,
such as chokes, contactors, relays are switched by contacts or semiconduc‐
tors, appropriate interference suppression has to be provided for them:
●
By arranging free-wheeling diodes in the case of d.c. operation
● In the case of a.c. operation, by arranging usual RC interference sup‐
pression elements depending on the contactor type, immediately at the
inductance
Only the interference suppression element arranged immediately at the in‐
ductance does serve this purpose. Otherwise, the emitted noise level is too
high which can affect the function of the electronic system and of the drive.
If possible, mechanical switches and contacts should only be realized as
snap contacts. Contact pressure and contact material must be suited for the
corresponding switching currents.
Slow-action contacts should be replaced by snap switches or by solid-state
switches, because slow-action contacts strongly bounce and are in an unde‐
fined switching status for a long time which emits electromagnetic waves in
the case of inductive loads. These waves are an especially critical aspect in
the case of manometric or temperature switches.
Bosch Rexroth AG DOK-RCON02-FV*********IB01-EN-P
Rexroth Frequency Converter Fv
160/219
Technical Data