DSC RM-2

The DSC RM-2 is an end-of-line power supervision relay that is designed to be used with 4-wire smokes. The device will notify users in the event that the smoke detectors are no longer receiving proper power. DSC created this device to be used in conjunction with their FSA-410 Photoelectric Smoke Detectors.

The device is wired to the smoke detectors, following a diagram that is provided in the device's installation manual. It will fit into a 1.5" double gang electrical box, mounted behind the smoke detector. Once installed, the RM-2 will monitor the smoke detector's power input. If you are using a reversing relay to cause all of the smoke detectors to sound when any smoke detector goes into alarm, the device will continue to operate normally even after a polarity reversal.

Because 4-wire smokes are normally open devices, and because having them close in the event of a power failure would cause a false fire alarm, a separate power supervision relay is needed. The power supervision relay is normally closed and is wired in series with the normally open smoke detectors. It should be placed at the last 4-wire smoke detector in the circuit. It must also be connected to the same power source as the smoke detectors. If the smoke detectors, and by extension the supervision relay, lose power, the supervision relay opens, causing an open circuit on the smoke detector zone. This will show up on the system as a check or trouble condition, instead of as an alarm.

Specifications:

• Operating Voltage: 10 VDC - 30 VDC
• Relay Contact Rating: 2A @ 30 VDC/VAC
• Current Draw: 25 mA
• Operating Temperature: 32°F - 120°F (0°C - 49°C)
• Operating Relative Humidity: 5% - 93% Non-Condensing
• Dimensions (H x W x D): 1 1/8" x 3 3/8" x 7/8" (28.5mm x 86mm x 21mm)
• Supported Wire Gauges: 14 AWG - 22 AWG