Capacity Expansion for Morley-IAS ZXSe and ZX Fire Alarm Panels
The Honeywell Morley-IAS 795-072-100 loop driver card is primarily deployed to expand detection loop capacity across modular analogue addressable fire alarm control panels. System integrators and panel builders utilize this plug-in daughterboard to scale Morley-IAS ZX2Se panels from a single loop to two loops, as well as expanding Morley-IAS ZX5Se panels up to five distinct loops. Because the card mounts internally onto dedicated slots on the control panel motherboard using direct plug-in pin headers, fire alarm technicians can expand coverage across commercial buildings, production facilities, and distribution centers without replacing the primary enclosure or main control hardware.
Panel architecture mandates that all loop driver cards installed within an individual ZXSe panel chassis run the identical Morley-IAS protocol. However, across networked multi-panel fire safety installations, separate panels running Morley-IAS loop drivers can interconnect seamlessly with panels utilizing other supported protocols.
High-Density Addressable Detection and Interface Topologies
Engineers deploy the 795-072-100 driver card to manage complex, mixed-device detection topologies on a single physical circuit. Each loop card controls up to 198 total addresses, partitioned into a capacity of up to 99 analogue addressable detector/sensor addresses alongside up to 99 module addresses. This architecture is designed for facilities that require varied peripheral types operating on the same circuit loop:
- Analogue Sensors: Morley-IAS optical smoke sensors and thermal heat sensors distributed through occupied areas, processing rooms, and technical spaces.
- Input and Supervisory Modules: Addressable monitor modules connected to third-party equipment such as sprinkler flow switches, pump status monitors, and gas detection interfaces.
- Output and Control Modules: Output control modules configured to trigger fire damper closure, ventilation shutoff, air handling units, and auxiliary relay functions during an alarm event.
- Circuit Protection and Legacy Interfaces: Loop isolator modules to provide sectional circuit isolation, as well as conventional zone interface modules allowing legacy conventional detector zones to be integrated directly onto the Morley-IAS addressable loop.
Class A Fault-Tolerant and Class B Wiring Configurations
The 795-072-100 loop driver card accommodates both Class A (closed return loop) and Class B (open spur) field wiring topologies. In critical infrastructure or large commercial premises where cable integrity and continuous device polling are mandated even in the event of an open circuit fault, the Class A closed return configuration is installed. For localized or branch applications, Class B spur circuits are supported.
Field engineers must calibrate electrical loads to ensure that total active and quiescent demands remain within the card's continuous rating. The card delivers a maximum continuous loop drive current of 460 mA (nominal 440 mA continuous drive current per loop) at a nominal 24 V DC operating loop voltage, while drawing an internal quiescent power consumption of 20 mA (excluding connected field devices). Circuit planning must maintain loop line resistance within 40 Ohms maximum and overall cable capacitance within 0.5 µF maximum to avoid polling delays, communication drops, or supply fault conditions.
Commissioning, Diagnostics, and Field Upgrades
During initial site installation and system recommissioning, technicians rely on panel-level diagnostic capabilities enabled by the loop card. The card supports the ZXSe panel AUTOLEARN routine, an automated internal diagnostic function that interrogates the loop circuit to scan, detect, and address all connected field sensors and modules. Furthermore, the 795-072-100 features integrated double address detection, which alerts technicians when two devices on the loop have been set to the same physical address, preventing silent device drops and configuration oversights.
During installation or card replacement in operating panels, the onboard loop voltage jumper must be aligned to the required driver position before energizing the control equipment with main AC supply or standby battery power (they are not included). This configuration maintains compliance with EN 54-2 and EN 54-4 system standards across the fire alarm network.
