Rosslare AC-225E - Normally Open Supervised Single Resistor Input Connection; Normally Open Supervised Double Resistor Input Connection; Figure 12: Normally Open Supervised Input (Single Resistor)

Input and Output Connections
22 AC-225x Series Hardware Installation Manual
4.1.3 Normally Open Supervised Single Resistor Input Connection
Connect an 8.2 kΩ resistor in parallel to the input switch contacts.
Normally Open Supervised Input has 3 states:
 Switch Open – Normal State:
Loop resistance = 8.2 kΩ
 Switch Closed – Abnormal State:
Loop resistance = 0 (short circuit).
 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 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.
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.