Description

Honeywell 2MLL‑C42A Snet Serial Communication Interface Module

Technical Specifications

• Part Number: 2MLL‑C42A
• Brand: Honeywell (MasterLogic‑200 PLC series)Honeywell
• Warranty: One Year
• Power Supply: Powered by MasterLogic‑200 rack backplane; typical consumption 100 mA
• Ports: 2‑channel independent RS‑422 differential serial interface (Snet I/F)
• Baud Rate: 300‑115200 bps asynchronous; configurable parity, data‑bit, stop‑bit parameters
• Max Transmission Distance: RS‑422 up to 500 m multi‑drop bus topology
• Operating Temperature: 0 °C ~ +55 °C cabinet‑mount; storage ‑20 °C ~ +70 °C
• Humidity: 5‑95 % RH non‑condensing
• Interface: Removable green screw‑clamp terminal blocks; front‑panel diagnostic LED indicators; backplane mating connector for MasterLogic‑200 base rack
• Supported Protocols: Honeywell Snet; Modbus‑RTU / ASCII slave mode; point‑to‑point & multi‑drop bus networking
• Protection: ESD & surge suppression; channel‑level communication‑fault diagnostic reporting
• Dimensions / Weight: 127 mm × 127 mm × 25 mm; approx 0.12‑0.2 kg
• Protection Class: IP00 plug‑in rack‑mount module

Product Overview

The 2MLL‑C42A is a dual‑channel RS‑422 serial communication interface module for Honeywell MasterLogic‑200 PLC / Experion‑LX DCS platform. It implements Snet bus or Modbus‑RTU serial communication, connecting PLC CPU to third‑party serial instruments, RTU, HMI and legacy field devices. Differential RS‑422 physical layer delivers strong noise‑immunity for long‑distance wiring in heavy‑EMI plant cabinet environments. Removable terminal blocks enable module replacement without re‑terminating field cables.

This module addresses serial‑gateway challenges: long‑distance differential serial‑bus connection for industrial‑field instruments, flexible Modbus‑RTU integration for legacy equipment, drop‑in spare‑part compatibility for existing MasterLogic‑200 retrofit‑maintenance projects. DCS‑PLC engineers, power‑plant and petrochemical‑site maintenance technicians and retrofit integrators benefit most. Typical applications: power‑utility, oil‑gas, pulp‑and‑paper plant control‑systems serial‑device interconnection.

Key Application Notes

• MasterLogic‑200 rack‑mount module; cannot operate standalone; must install into MasterLogic‑200 main/expansion base rack slotHoneywell
• Two independent RS‑422 channels, not RS‑232; proper bus‑termination resistor required for multi‑drop wiring
• Not hot‑swap capable: rack power must be removed before module replacement
• Configuration of baud‑rate, protocol and station‑address implemented via Honeywell MasterLogic programming software
• Original OEM production is obsolete; widely‑used aftermarket surplus/refurbished spare part
• Conformal‑coated variant (‑CC suffix) available for high‑humidity, high‑contaminant cabinet environments
• Origin: Korea / USA; follow Honeywell MasterLogic‑200 serial‑communication installation manual for bus‑wiring rules