18
900 Series V5.0: Installation Guide, April 1999
3.3.5.
Mini Switch Monitoring Unit with an interrupter - II951
There are six wires, two for the loop connections, two for driving a remote indication and
two for an external switch connection.
Figure 13: Wiring options for the Mini Switch Monitor Plus
To install a Mini Switch Monitoring Unit with an interrupter:
1. Mount the Switch Monitor Unit. Use suitable terminal blocks when connecting it to the
flying leads. If a remote LED is fitted, a six-way terminal block is needed, otherwise
four ways are enough.
2. Connect the communication line to the Line 1 and Line 2 inputs. The inputs are
unpolarised, but it is recommended that Line 1 is kept negative for consistency.
3. There are two wiring options for the Mini Switch Monitor as shown in Figure 13.
Connect the switch contacts to the switch inputs as desired. Installing the 20 kOhm
end-of-line resistor enables the switch inputs to be monitored for open or short
circuits.
4. A software controlled remote indicator (alarm LED) output is supplied. Connect an
external LED to the remote outputs. During installation orientate the device correctly if
the LED needs to be visible. The LED output drives the standard Aritech remote
indicator.
Fire contacts
Red
Black
Yellow
Green
White -
Remote LED
LINE
2*
LINE
1*
20 kOhm ± 10% 1/3 W
470 Ohm
fire contacts
Fire and fault contacts
Red
Black
Yellow
Green
White -
LINE
2*
LINE
1*
Remote LED
470 Ohm
fire contact
20 kOhm
± 10% 1/3 W
Fault contact
* L1 and L2 are polarity insensitive but it is recommended to keep L1 negative for continuity.
