4U iSTAR Pro as a Burglar Alarm System Unit
53
The configuration in the host computer determines how the hardware module
and the reporting software will respond to the various conditions that are
detected.
UL Compliant
Supervision
The indication of whether a monitor point is Normally Closed (NC) or
Normally Open (NO) is done by how the resistor network is wired in
conjunction with the alarm device to form a supervised End Of Line (EOL)
resistor alarm zone. The host system views monitor points as being either
logically true or false. Software House wires NO and NC supervised input
circuits differently because it makes the software implementation more logical.
The two different methods result in an alarm loop resistance of 1K ohms being
the Secure supervised state whether the monitor point is connected as a NO or
NC alarm loop. Since the hardware wiring defines NO and NC, the software
works with inputs that are simply either logically true or false.
Wiring for Alarm Zones
To wire a NO alarm loop to an input circuit, connect a 1 K Ω EOL resistor across
the input and another EOL in series with the switch, as shown below. This
circuit will provide 5-state supervision.
To wire a NC alarm loop to an input circuit, connect a 1 K Ω EOL resistor across
the switch and another EOL in series with the input, as shown below. This
circuit will provide 5-state supervision.
Single Device Alarm Zone –
Ranges of resistance
Input Status
Resistance
Comment
Short 0 - 100 Ω Wires crossed
Line Fault 101 Ω – 360 Ω Wrong resistor
NO Alarm 361 Ω – 750 Ω 500 Ω
Secure 751 Ω - 1450 Ω 1K Ω
NC Alarm 1451 Ω - 2980 Ω 2K Ω
Line Fault 2981 Ω – 11.8K Ω Wrong resistor
Open Loop > 11.8K Ω Cut wire
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