Installation 
2.4  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 
Output #1 or #2 
Indicator Status 
N.O. Open 
Off 
N.C. Closed 
 
Off 
Open 
Off 
N.O. 
Closed 
On 
Closed 
Off 
On 
N.C. 
Open 
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 de-energize and thus the 
alarm contacts will close. 
 
Table 2-3  Alarm Relay Contact Information 
Variable NOT in Alarm State  Variable in Alarm State Unit  
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 
12/04  UDC3200 Universal Digital Controller Product Manual  17