User guide

Inputs, Relay Outputs, and Power Status
Rev 1.0 Jan.12 41
5: Inputs, Relay Outputs, and Power Status
• Capturing External
Events
• Power Modes and
Information
The AirLink GX440 can be configured to monitor input, respond to specific types
of events, and even trigger digital output. The AirLink GX440 can also be
configured to change its power mode in order to conserve power. These features
can be configured to fit your needs.
Capturing External Events
The AirLink GX440 is equipped with an I/O port interface which includes 1 low
power timer enable input and 1 digital I/O. These may be connected to sensors
and switches to monitor status and remotely control equipment.
AirLink GX440 board supports a low power timer enable input pin and a digital I/O
pin which are connected to the CPU processor. The I/O signal comes in from the
power connector, through a polyswitch resettable fuse, and ties into the CPU pins
with protection circuitry.
Digital Input
Digital Input can be used in two different modes: the switch mode or the voltage
sensing mode.
Figure 5-1: Digital Input Contact Closure
The switch mode senses contact closures. The digital input can report either an
open or closed state, and can be wired to a ground signal via a switch. When the
switch is open, the input reads “3.3V”. When the switch is closed, the input reads
“OV”.
Digital I/O
Ground
Contact Closure
Digital Input