How do you use the Recorder's Alarm Output Connection.?.
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Alarms on Vehicle Recorders:
The recorder "Alarm" output terminal switches to 0v (zero supply volts) when an alarm condition is present on any temperature sensor input. In some models a facia mounted LED lamp illuminates at the same time.
The adjacent "Vin" connection is used in conjunction with the "Alarm" pin. to power any device connected between the two connection pins. The "Vin" connection is connected to the + Battery supply and gives out the same voltage as appears at the battery supply input. Namely 12 or 24 volts depending on the battery driving the recorder.
The Alarm circuit "Vin & Alarm" can switch up to 1 Amp. If you wish to switch a remote alarm lamp or other indicator it is best to use an LED type. It is not recommended to switch incandescent bulbs using this output since they have a very hich inrush current at start up that may damage the Alarm output circuitry.
If it is nesessary to switch currents of higher than 1 Amp from the alarm circuit simply connect a sutable relay coil between the "Vin & Alarm " terminals and use its contacts to switch the load. If the coil of the relay is polarised connect the + side of the coil to "Vin".
Alarms on Cold Store Recorders:
All the above comment are true for Cold Store recorders, but since the unit is powered from the mains supply the +ve output on Vin will be around +15 to +16 volts DC. So the Alarm circuitry relay used must operate at around 15v dc.
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