Mechanical Mounting, Field Wiring & Commissioning Guidelines

The Honeywell Morley-IAS MI-DISO loop isolation module is supplied as a compact bare unit measuring 93 mm in height, 94 mm in width, and 23 mm in depth, with a net unit weight of 62 g. Because the unhoused module carries an ingress protection rating of IP30, it requires dedicated mechanical hardware depending on the installation environment. For surface wall-mount deployments, the module must be paired with the external M200E-SMB surface-mount enclosure, which elevates the ingress protection rating to IP50. For control panel enclosures or distribution boards utilizing standard 35 mm DIN rails, the module requires the M200E-DIN mounting clip adapter (or M200E-PMB clip ecosystem). Neither mounting accessory is included in the base module package and must be specified separately.

Field Wiring & Plug-In Terminal Connections

The unit features detachable plug-in screw terminal blocks designed to simplify rough-in wiring and speed up commissioning. Technicians can route and terminate loop cables into the removable terminal blocks prior to affixing the module chassis. The screw terminals accept solid or stranded conductors up to a maximum wire gauge of 2.5 mm². This plug-in terminal architecture allows rapid module replacement during maintenance without disconnecting individual loop field cores from their terminal points.

Loop Configuration & Device Capacity

When engineering Morley-IAS analogue addressable fire alarm loops (including Morley-IAS ZX and DXc series control panels), the MI-DISO module must be positioned along the two-wire circuit to section off wiring runs. System design rules allow a maximum of 25 addressable devices or sensors between consecutive isolator modules. The module operates across an analogue addressable loop voltage range of 15 to 30 V DC, drawing a low quiescent standby current of 200 µA maximum at 24 V DC. In normal operating conditions, the module maintains a minimal switch-on resistance of 0.065 Ω maximum at 15 V DC to avoid parasitic voltage drops across the signalling circuit.

Fault Isolation & Environmental Tolerances

Upon detection of a wire-to-wire short circuit, the internal bilateral solid-state switches activate within a fault detection delay window of 100 ms to 400 ms, automatically isolating the damaged loop segment and preventing entire loop collapse. The MI-DISO is designed to operate continuously across an ambient temperature range of -20 °C to +60 °C and relative humidity levels between 0% and 95% (non-condensing).

Address Configuration & Diagnostic Inspection

The module features onboard decade rotary switches and a diagnostic tri-colour status LED that are both engineered for multi-angle visibility in two orthogonal planes. When installed inside the M200E-SMB surface box, both the decade address switches and the tri-colour LED indicator can be clearly inspected through the transparent viewing window of the cover without disassembling or opening the enclosure.