Rosslare AC-425 - Normally Open Supervised Double EOL Resistor Input Connection; Figure 12: Normally Open Supervised Input (Single Resistor); Figure 13: Normally Open Supervised Input (Double Resistor)

Input and Output Connections
22 AC-425 Hardware Installation and User Manual
 Open circuit across input terminals – Trouble State:
Loop resistance = Infinite (open circuit).
Figure 12: Normally Open Supervised Input (Single Resistor)
4.1.4 Normally Open Supervised Double EOL Resistor Input
Connection
Connect a 2.2 kΩ resistor in series to the input switch contacts.
Connect an 8.2 kΩ resistor parallel to the input switch contacts.
A Normally Open Supervised Input has 3 states:
 Switch Open – Normal State:
Loop resistance = 10.4 kΩ
 Switch Closed – Abnormal State:
Loop resistance = 2.2 kΩ
 Open circuit (infinite loop resistance) or short circuit (0 resistance) across
input terminals – Trouble State
Figure 13: Normally Open Supervised Input (Double Resistor)