User manual - COUNTER SLB-94
Due to possible significant interference in industrial installations appropriate measures
assuring correct operation of the unit must be applied. To avoid the unit of improper
indications keep recommendations listed below.
Avoid common (parallel) leading of signal cables and transmission cables together with
power supply cables and cables controlling induction loads (e.g. contactors). Such cables
should cross at a right angle.
Contactor coils and induction loads should be equipped with anti-interference protection
systems, e.g. RC-type.
Use of screened signal cables is recommended. Signal cable screens should be
connected to the earthing only at one of the ends of the screened cable.
In the case of magnetically induced interference the use of twisted couples of signal
cables (so-called spirals ) is recommended. The spiral (best if shielded) must be used
with RS-485 serial transmission connections.
In the case of measurement or control signals are longer than 30m or go outside of the
building then additional safety circuits are required.
In the case of interference from the power supply side the use of appropriate anti-
interference filters is recommended. Bear in mind that the connection between the filter
and the unit should be as short as possible and the metal housing of the filter must be
connected to the earthing with largest possible surface. The cables connected to the filter
output must not run in parallel with cables with interference (e.g. circuits controlling relays
or contactors).
Notes related to connection of encoders and control inputs:
Installation should be made accordingly to local law regulations, related to safety
and electromagnetic compatibility. Essentially following recommendation should be
preserved.
- use only shielded wires;
- the shield should be connected to metal case of the encoder,
- wires should be placed as close as possible to metal construction of the machine
and as fare as possible of inferencing wires ( e.g. supply of motors etc.)
- in case, while encoder is far off from the counter, and long wires must be used, it
is recommended to use additional protection wire (bold enough) between
counter's additional metal case and machine construction where encoder is
mounted .
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Summary of Contents for SLB-94
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