Installation
6 UDC2300 Universal Digital Controller User Manual 4/00
2.3 Control and Alarm Relay Contact Information
Control Relays
ATTENTION
Control relays operate in the standard control mode (that is, energized when output
state is on).
Table 2-2 Control Relay Contact Information
Unit Power Control Relay
Wiring
Control Relay
Contact
#1 or #2 Output
Indicator Status
N.O. Open
Off
N.C. Closed
Off
N.O. Open
Closed
Off
On
On
N.C. Closed
Open
Off
On
Alarm Relays
ATTENTION
Alarm relays are designed to operate in a Failsafe mode (that is, de-energized during
alarm sate). This results in alarm actuation when power is OFF or when initially applied,
until the unit completes self-diagnostics. If power is lost to the unit, the alarms will
function.
Table 2-3 Alarm Relay Contact Information
Variable NOT in Alarm
State
Variable in Alarm StateUnit
Power
Alarm
Relay
Wiring
Relay
Contact
Indicators Relay
Contact
Indicators
N.O. Open Open
Off
N.C. Closed
Off
Closed
Off
N.O. Closed Open
On
N.C. Open
Off
Closed
On