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 DL205 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 DL205 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
DL205 PLC
Output Module
Loads
AC Power or 125VDC Bases
+
–
Inputs
Com.
Outputs Com.
Input Module
Power Input
DL205 PLC
Output Module
Loads
DC Power
+
–
+
–
Inputs
Com.
Outputs Com.
3
Chapter 3: I/O Wiring and Specifications
3–3
DL205 Installation and I/O Manual, 2nd Edition