Extron electronics IPCP Pro Series User Manual page 40

Digital input — To allow the IPCP to monitor external devices that do not use RS-232
communication, connect a switch, motion sensor, moisture sensor, tally feedback
output, button pad, relay contact, or a similar item to a Flex 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.
For Flex I/O ports, threshold voltages are adjustable. Default 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, which you
can use if the connected device does not provide its own power.
Flex I/O digital input with pull-up disabled
•
Digital input is triggered by an external switch or voltage between the digital
•
input pin and ground.
Threshold adjustments can be made from 0.0 VDC to 25.3 VDC in 100 mV steps.
•
Example application, digital input without pull-up: occupancy sensor
•
connection
+5.0 V
SW 2
A/D
CTL
Converter
Figure 29. Flex I/O Digital Input Application:
Occupancy Sensor, Without Pull-up
Room occupied: logic high, front panel LED is off.
Room unoccupied: logic low, front panel LED is lit.
Occupancy sensors typically supply +24 VDC (logic high) when
NOTE:
occupancy is detected. After a set time with no occupancy, the sensor
supplies 0 VDC (logic low).
1k ohms
Flex
I/O
Voltage
SW 1
Protection
GND
IPCP Pro Series • Hardware Features and Installation
Occupancy
Sensor
Control
Signal
Ground
32