Omron CV500 Installation Manual page 76

Wiring I/O Units
Inductive Load Surge
Suppressor
Input Units
Voltage Inputs
Voltage output
+
Output
0 V
Input Leakage Current
When an inductive load is connected to an I/O Unit, connect a surge suppressor
or diode in parallel with the load, as shown in the following diagram. The diode
will adsorb the back electromagnetic field generated by the load.
Relay Output Unit
Triac Output Unit
Relay Output Unit
Transistor Output Unit
where for the surge suppressor,
Resistor: 50
Capacitor: 0.47 F
Voltage: 200 V
and the diode,
Breakdown voltage: at least 3 times load voltage
Mean rectification current: 1 A
Do not wire voltage inputs as shown on the left below.
Sensor
power
supply
IN DC input
COM (–)
Incorrect
When two-wire sensors, such as photoelectric sensors, proximity sensors or
limit switches with indicators are connected to the PC as input devices, the input
bit may be turned ON erroneously by leakage current. In order to prevent this,
connect a bleeder resistor across the input to reduce the input impedance.
Sensor
IN
L Diode DC input
COM
L
OUT
Surge suppressor
COM
L
OUT
Diode
COM
Voltage output
+
Output
0 V
Correct
Input
power
supply
Bleeder
resistor
Section 3-5
+
COM (+)
IN DC input
Sensor
power
supply
PC
R
63