Air Products GASGUARD TE10, Installation, Operation And Maintenance Manual, Page: 89 / 196

Section 4: Electrical Connections
Revision – August 2005 Page 4 - 9
4.4.1 Supervised Inputs
The system supports 2 supervised inputs from the customer interface. Supervised
inputs are analog inputs, which are monitored via a window comparator. These inputs
are monitored for normal operation, alarm type, and fault conditions.
A normally open switch is to be used as an input device. This switch must have a 750
ohm resistor in parallel with the contacts and a 1K ohm resistor in series with the
contacts. When the switch contacts are open the circuit will provide a signal, which
represents a normal operating condition. When the switch contacts are closed the
circuit will provide a signal which indicates an alarm condition. An open wire in this
circuit, or a short circuit, will produce an out of range signal, which indicates a circuit
fault.
Switch contacts must be rated for 20ma @ 24Vdc.