Omron ZEN Operation Manual page 69

Wiring
12 to 24 VDC
Precautions for Correct Use
■ CPU Units with 20 I/O Points
12 to 24 VDC
COM
12 to 24 VDC
COM
Connecting Positive Common (NPN Connection)
COM
CPU Unit with
10 I/O points
• Apply the power supply voltage through a relay or switch in such
a way that the voltage reaches the rated value within 4 s. If the
voltage is applied gradually, the power may not be reset or
unstable output operations may result.
• Connect the COM terminals before turning ON the power supply.
Not connecting the COM terminals or connecting them after
turning ON the power supply may cause malfunctions.
Connecting a Negative Common (PNP Connection)
I0 I1 I2 I3 I4 I5 NC
CPU Unit with
20 I/O points
Connecting Analog Input Devices to Input Terminals Ia
and Ib
I 0 I 1 I 2 I 3 I4 I5 N C
CPU Unit with
20 I/O points
Note: If a positive common is used,
Input device
Input device
I6 I7 I8 I9 Ia Ib
I6 I 7 I 8 I 9 I a Ib
Section 2-2
analog input devices cannot be
connected to I4 and I5.
Note: When connecting
an analog input
device, always
connect the
negative side to the
COM terminal.
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