Do-more H2 Series PLC User Manual, 1st Edition, Rev. F - H2-DM-M
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Chapter 8: Installation and Wiring
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Powering I/O Circuits with the Auxiliary Supply
In some cases, using the built-in aux24VDC supply can result in a cost savings for your
control system. It can power combined loads up to 300mA. Be careful not to exceed the current
rating of the supply. If you are the system designer for your application, you may be able to
select and design in field devices which can use the +24VDC auxiliary supply.
All AC powered and 125VDC bases feature the internal auxiliary supply. If input devices AND
output loads need +24VDC power, the auxiliary supply may be able to power both circuits as
shown in the following diagram.
The 12/24VDC powered bases are designed for application environments in which low-
voltage DC power is more readily available than AC. These include a wide range of
battery–powered applications, such as remotely-located control, in vehicles, portable machines,
etc. For this application type, all input devices and output loads typically use the same DC
power source. Typical wiring for DC-powered applications is shown in the following diagram.
Input Module
Auxiliary
+24VDC
Supply
Power Input
Do-more PLC
Output Module
Loads
AC Power or 125VDC Bases
+
–
Inputs Com.
Outputs Com.
Input Module
Power Input
PLC
Output Module
Loads
DC Power
+
–
+
–
Inputs Com.
Outputs Com.
Do-more