User`s manual

Chapter 5 — Using the IF30 GPIO Interfaces
78 IF30 Fixed Reader User’s Manual
Driving a DC Relay to Control an AC Load
While the IF30 outputs are designed to switch DC loads, they can
drive relays that control AC loads. The illustration on the next page
shows how to connect such a system to an IF30 output.
Driving a DC Relay: The external relay provides dry contacts for controlling the
AC motor.
Using the Power Interface
The IF30 GPIO interface provides 12 VDC at 0.5 A for powering
external inputs and loads, eliminating the need for an external DC
supply and simplifying the system installation.
The GPIO interface power has an internal thermal fuse that trips if
the load exceeds 0. 5A. The fuse is self-recovering once excessive load is
removed.
The total load on the GPIO interface power must stay within the 0.5 A
limit. When you design a system that uses the GPIO interface power,
be sure to complete a power budget assessment to ensure that the
supply is adequate for the system.
AC motor
120 -230
VAC
External
relay
+Output
+12 V
Ground
-Output
Note: In many installations, the relay and AC wiring must be placed in
an enclosure that meets local fire code regulations.