Extron electronics HC 400 Series User Manual page 34

Digital 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.
Example application, digital input without pull-up: occupancy sensor
•
connection (shown below)
+5.0 V
1k ohms
SW 2
CTL
SW 1
Figure 15. Digital I/O Digital Input Application:
Occupancy Sensor, Without Pull-up
Room occupied: logic high, switch 1 open.
Room unoccupied: logic low, switch 1 closed.
NOTE: Occupancy sensors typically supply +24 VDC when occupancy is
detected. After a set time with no occupancy, the sensor supplies 0 VDC.
Digital
I/O
Voltage
Protection
GND
HC 400 Series • Hardware Features and Installation
Occupancy
Sensor
Control
Signal
Ground
26