User's Manual

Chapter Two Installation
Man_455U Rev 1.0 Page 17
2.5 Discrete I/O Point
The 455U provides a single connection which can be used as a
discrete input for alarms, or a discrete output, to control remote
equipment,
2.5.1 Using The discrete I/O point as an Input
When using the DIO pin as an input, it is activated by
connecting the DIO pin to COMMON, This can be done using
a voltage free contact (Relay or Switch) or a
NPN transistor to common. To read the status of
the Input, ensure the output function is disabled
(AT#O0) and read S-Register S33.
2.5.1 Using The discrete I/O point as an
Output
When using the DIO pin as an output, it acts as an NPN transistor to common. It can be wired
to an indicator or alarm (Max 24VDC, 500mA) or to a relay to remotely operate equipment.
The output is controlled using the AT#O command (AT#O0 turns off, AT#O1 turns on).
455U
DIO
COM
455U
DIO
COM
+
30V Max
-
Inductive Load
+
30V Max
-
Non
-Inductive Load
455U
DIO
COM