Precautions for i/o modules – Toshiba Programmable Controller PROSEC T3 User Manual
Page 60
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3. Precautions for I/O Modules
(4) If the AC lines are installed in parallel with high frequency or
power lines, induced current may cause erroneous input. In this
case, take necessary countermeasures as follows:
•
Change the installation route of AC input lines so that
they are not parallel with power lines and high
frequency lines.
•
Use twisted-pair cables as input lines.
•
Use shielded cables as input lines.
•
Use relays at the leading in the control panel (the relay
must satisfy larger ON current).
•
Install a bleeder resistor to lower the input impedance.
(5) If the input module and an inductive load are connected in
parallel, a surge voltage generated at both-ends of the load
when the contact is changed to OFF may cause a malfunction of
the PLC. In this case, install a surge absorption element in
parallel with the load to suppress the surge voltage.
Input module
)
)
-----------------------------------------------------------
-0^
Hl-O-
----------Inductive load
^ ^ Surge absorption element (snubber circuit, etc.)
52
PROSEC T3