BY12512d_e.doc / Mai-08
Page 35 / 52
Where you use one common encoder for feedback of the drive and feedback
for the BY125 at the same time, there may come up interference problems.
You can use an impulse splitter to eliminate any kind of problems. In some
applications, the common encoder would also work fine when it is supplied
by the drive and the BY125 operates in fully differential mode like shown.
Encoder
/A
A
B
/B
Screen
4 (NC)
4 (NC)
9
1
2
3
5 (NC)
Do connect Pin 4 and pin 5 of the
By125 encoder connector!
not
10.3.
Screening
It is mandatory to use screened cables for encoders and analogue signals. Correct connection
of the screens is essential for trouble- free function.
Control inputs like Reset, Trim etc. can be unscreened, provided the cable length does not
exceed 5 meters. Use screened cables for longer length also.
The following basic screening rules must be observed:
a) With impulse cables (encoders), the screen must be connected at both
ends.
b) Analogue signals and control lines need screens connected only on one
end.
c) The screen potential must be the internal GND of the BY125 unit (not
earth potential! See GND terminals on terminal strip). Since, in general,
the minus wire of the 24V power supply will be earthed anyway, the
screens will automatically receive earth potential when connected to
GND.
d) At its peripheral end, the screen should not be tied to earth nor touch
metallic parts that are earthed. Where you use an encoder with plug
connection, the screen should not touch the metallic housing of this
connector! (With the encoder mounted at the machine, this would be an
illegal earth loop).
