Mounting
3
♦
Place RT28U
into a 90 x 90 mm (for case 'B'),
90 x 42 mm (for case 'H'), or
42 x 90 mm (for case 'V') panel cut-out.
♦
Tighten it into place using the enclosed
mounting brackets.
Electro-Magnetic Interference (EMI) Issues
Important note:
A built-in RC noise
suppression circuit may
be connected in parallel
with relay contacts.
Full AC voltage isolation
may NOT be provided
when relay contacts
are open.
Small AC current
(
≈
1.5 mA at 230 VAC)
may still flow through
the RC circuit.
♦
All signal wires must be shielded.
They must not be packaged together
with power cables.
♦
Never lay the signal wires close
to inductive or capacitive noise sources,
such as relays, contactors, motors, etc.
♦
All shields have to be grounded ONLY
at one end, as closer as possible
to the controller terminals.
♦
Avoid sharing supply lines with powerful
consumers, especially with inductive loads,
switched on and off.
♦
To stop unwelcome interference signals
entering through the power supply lines,
use shielded 1:1 isolation transformer.
♦
Shunt all switched (not only those switched
by the controller) inductive consumers
with special suppression networks:
RC group and varistor - for AC loads,
or diode - for DC loads.
♦
If the controller operates in a very powerful
EMI area, it has to be mounted inside
a grounded metal shielding box.
♦
To protect the interface
from electro-magnetic disturbances,
follow the RS485 standard guidelines.
