The Honeywell 2MLL‑CH2A, also cataloged as the 2MLL‑CH2A serial communication module, provides dual‑channel RS232C and RS422/485 communication for MasterLogic systems. It executes asynchronous serial transmission with configurable framing, baud rates, and diagnostic monitoring.
Hardware Specifications
Parameter
Specification
Model
2MLL-CH2A
Brand
Honeywell
Origin
USA
Weight
119 g
Core Performance Indicators
1 ch RS232C, 1 ch RS422/485, modem support on RS232C, asynchronous communication, up to 115200 bps, photo‑coupler isolation, auto‑scan diagnostics
Serial Interface & Protocol Configuration
The module supports one RS232C channel and one RS422/485 channel. RS232C allows modem connection for remote communication. All communication parameters are configured through SoftMaster‑NM, including:
Transmission distance is specified as 15 m for RS232C (extendable via modem) and 500 m max for RS422.
Network Diagnostics & LED Indicators
Diagnostic functions include auto‑scan, frame monitor, link monitor, and loop‑back testing. LED indicators provide real‑time status:
RUN
I/F
TX
RX
ERR
These indicators support rapid identification of communication faults or link instability.
Frequently Asked Questions
Q: Can the RS232C port connect directly to a modem A: Yes. Modem connection is supported only on the RS232C channel.
Q: How far can RS422 communication be extended A: Up to 500 m maximum, as specified.
Q: Are communication parameters configurable per channel A: Yes. All framing and baud rate settings are adjustable through SoftMaster‑NM.
Field Installation Guidelines
Route RS232C and RS422/485 cables separately from high‑current conductors to reduce noise. Maintain proper shielding and ground reference for long‑distance RS422 runs. Ensure connectors are fully seated before enabling communication. Use loop‑back and frame‑monitor diagnostics during commissioning to verify stable link performance.
