Omron CS1W-NC113 - REV 02-2008, Manual

Page: 53 / 350

3-4 Section Wiring
40
3-4-4 Wiring Precautions
Operational errors such as dislocation can occur in most electronic control
devices if they are subjected to electronic noise from nearby power lines or
loads. Recovery from such errors is usually very difficult and time consuming. To
avoid such noise-generated operational errors and improve system reliability,
always observe the following precautions in wiring the system.
Be sure to use the sizes and materials indicated in the specifications when con-
necting power lines and cables.
Power lines (e.g., AC power supply, motor power line) and control lines (e.g.,
pulse output lines, external I/O signal lines) must be wired separately. Never put
these lines into the same duct or make them into a single bundle.
•
Attach a multi-layer ceramic capacitor of a thickness of less than 1
µ
F to the
pulse output power supply to improve noise resistance.
•
Do not use a 24--VDC or 5-VDC power supply for pulse output in common with
the power supply for other I/O.
•
Use shielded cable for control lines.
•
Connect the shielded cable to the frame ground at both the PCU and the drive.
•
Attach a surge absorber to all inductive loads, such as relays, solenoids, and
solenoid valves.
+
DC
--
Diode for surge
absorption
AC Surge
absorber
RY RY
DC relays AC relays
Solenoid Surge absorber
Solenoids, etc.
Note Connect the diode and surge absorber as close as possible to the relay. Use a
diode capable of withstanding a voltage five times higher than the circuit voltage.
•
Insert a noise filter into the power supply inlet if noise enters the power line
(e.g., when it is connected to the same power supply as an electric welder or an
electric spark machine or when there is any supply generating high frequency
noise).
•
Connect to a ground of 100
Ω
or less and use the thickest possible wire, greater
than 1.25 mm
2
.
•
Twisted-pair cable is recommended for power lines.