Extron electronics HC 404 User Manual page 25

Digital I/O
Digital I/O (digital input/output) ports — To allow the HCR 102 receiver to monitor
M
devices to trigger events, connect switches, sensors, LEDs, relays, or similar items to
these ports (see figure
with or without +5 VDC pull-up. These ports can trigger events or functions (such as
triggering relays, issuing commands, or sending an e-mail) that have been configured
using Global Configurator. By default these ports are set to digital input mode with
pull-up disabled.
DIGITAL I/O
HCR 102
Rear Con gure each port as a digital input or output,
Panel with or without +5 VDC pull-up. Use these ports to:
1 2 G 3 4 G
• Monitor or trigger events and functions (toggle relays,
issue commands, send e-mail), once con gured.
• Trigger LEDs, incandescent lights, or other devices
that accept a TTL signal.
Ground
Switch,
G
4 Sensor
3
G
Indicator
2
LED
1
Figure 7. Digital I/O Port Wiring Examples
Digital input — To allow the HCR 102 to monitor external devices that do not use
RS-232 communication, connect a switch, motion sensor, moisture sensor, tally
feedback output, button pad, or a similar item to a digital I/O port and configure it for
digital input. When configured as a digital input, the port is set to measure two states:
high and low. The port accepts 0 to 25.3 VDC input.
Threshold voltages are not adjustable. The thresholds are:
2.0 VDC — port on, logic low
•
2.8 VDC — port off, logic high
•
There is also an internal, selectable, pull-up resistor connected to +5 VDC.
Digital output — To trigger LEDs, lights, or other devices that accept a TTL signal,
or to provide contact closure control for projector lifts, motorized screens, room or light
switches via an Extron IPA T RLY4 or similar device, you can use one or more of these
ports as a digital output. When a port is configured for digital output, it offers two output
states: on and off.
When the port is set to an "on" state, (the circuit is closed), the I/O pin is connected
•
to ground. Output voltage is less than 0.5 volts.
When the port is set to the "off" state (the circuit is open), the output pin is not
•
connected. If the application calls for TTL compatibility, the digital output circuit can
be set up to provide a 2K ohm pull-up resistor to +5 VDC.
If the pull-up resistor is disabled, voltage output is determined by an external
•
source device.
If the pull-up resistor is enabled, voltage output is 4.3 VDC.
•
Each I/O port is capable of accepting 250 mA, maximum.
3, ), which can be configured as digital inputs or outputs,
M
Digital I/O (digital input/output)
Share the
same ground
among I/O
Wire
connections.
Nut
(Switches,
Device 4
sensors,
Device 3
relays, or
Device 2
Device 1
HC 404 System • Hardware Features and Installation
LEDs,
similar
items)
17