Mechanical Mounting Configurations: Surface Box and DIN Rail
The Morley-IAS MI-DMMI by Honeywell features a compact mechanical footprint measuring 93 mm (H) x 94 mm (W) x 23 mm (D) with an overall unit weight of 100 g. The module is engineered for versatile field deployment and supports two primary physical installation methods:
- Surface Wall Mounting: The unit can be housed directly inside a dedicated wall mount surface box using either the M200E-SMB or M220E/SMB enclosure. This setup protects electrical terminations while maintaining visual access to indicators.
- DIN Rail Mounting: When installing within industrial control enclosures, low-voltage distribution assemblies, or multi-module junction cabinets, the module attaches to standard DIN rails using an M200E-DIN mounting clip.
A central design feature is service accessibility: both the addressing decade rotary switches and the diagnostic indicators remain clearly visible through the mounting enclosure. Commissioning engineers and technicians can inspect unit status or verify loop addressing without dismounting the unit or opening the face cover.
Loop Addressing via Decade Rotary Switches
The MI-DMMI single-channel monitor module operates on the Morley-IAS intelligent fire alarm control panel signalling loop, requiring one dedicated address out of the ninety-nine available module addresses on the loop circuit.
Address setting is completed directly on the hardware via visible decade rotary selector switches. Technicians can adjust the rotary dials to the designated loop address using a standard screwdriver, eliminating the requirement for specialized electronic programming tools, handheld interrogators, or software-based addressing sequences during field installation.
Field Wiring and Electrical Terminations
Field connections are streamlined through plug-in wiring terminal blocks. This pluggable terminal block configuration allows field cabling to be pre-wired, continuity-tested, and serviced without unseating the module chassis from its mounting location.
- Signalling Line Circuit (SLC) Voltage: Operates across a 15 to 30 Vdc range. A minimum loop supply of 17.5 Vdc is required to ensure proper LED indicator operation.
- Loop Standby Current: Consumes a maximum of 310 µA at 24 Vdc during quiescent standby with no loop communication, and a maximum of 510 µA at 24 Vdc with polling once every 5 seconds and LED blink enabled.
- Integrated Short-Circuit Isolators: Built-in line isolators are incorporated directly on the signalling line circuit, fully compliant with EN 54-17 requirements to prevent single loop faults from disabling the entire loop segment.
- Monitored Input Circuit: Designed to monitor normally open dry contact initiation devices compliant with EN 54-18, including sprinkler supervisory valves, waterflow switches, pressure switches, and manual contact units. The circuit continuously evaluates normal, open-circuit, and alarm states.
Commissioning, Diagnostics, and Environmental Limits
System operational status is communicated locally via a tri-colour LED indicator visible across two viewing planes (front surface and profile light pipe):
- Pulsing Green: Normal interrogation and polling communication from the Morley-IAS fire alarm control panel.
- Steady Red: Active alarm initiation condition triggered by the connected field device.
- Blinking Yellow: Loop trouble, fault condition, or short-circuit isolator activation.
Install the MI-DMMI exclusively within environments conforming to its operating temperature range of -20 °C to +60 °C and an operating relative humidity limit between 0% and 95% (non-condensing).
