User`s manual

Chapter 5 — Using the IF30 GPIO Interfaces
74 IF30 Fixed Reader User’s Manual
IF30 Powered Input
Isolated Input Interface
This method is used to minimize noise induced by distance or
grounding. The isolated input avoids induced noise by referencing a
remote input to chassis return of the IF30. The illustration below
shows how to wire in this method.
Isolated Input Interface
Open Collector Interface
The input can be connected to an open collector interface of an
external device. This implies that the grounds are tied together for
two systems. The common ground can be a source of noise, so you
should follow good grounding practices for both the IF30 and the
input device.
In this situation, the IF30 provides power to the pull-up resistor for
the open collector. Connect the +Input pin to the +12 VDC source as
shown in the next illustration.
External
input
switch
+Input
+12 V
Ground
-Input
+
-
External
input
switch
10 -48 VDC
Twisted
pair
-Input
+Input