45
Wiring Section 2-2
Connecting Positive Common (NPN Connection)
Precautions for Correct Use
• 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.
■ CPU Units with 20 I/O Points
Connecting a Negative Common (PNP Connection)
Connecting Analog Input Devices to Input Terminals Ia
and Ib
COM
CPU Unit with
10 I/O points
Input device
12 to 24 VDC
Note: If a positive common is used,
analog input devices cannot be
connected to I4 and I5.
COM
I5 I6NC I7 I8 I9 Ia IbI0 I1 I2 I3 I4
CPU Unit with
20 I/O points
Input device
12 to 24 VDC
COM
I5 I6NC I7 I8 I9 Ia IbI0 I1 I2 I3 I4
CPU Unit with
20 I/O points
12 to 24 VDC
Note: When connecting
an analog input
device, always
connect the
negative side to the
COM terminal.
Z211-E1-03.book Page 45 Friday, November 21, 2008 10:38 AM