Honeywell MasterLogic-200 Modules: 2MLR-CPUH/F-CC CPU,

Technical Dossier

Product Details And Specifications

Honeywell MasterLogic Series Technical Notes

The Honeywell MasterLogic-200 (ML-200) is a modular programmable logic controller platform deployed extensively across global heavy industry, including petrochemical refineries, nuclear power auxiliary systems, offshore platforms, and large-scale chemical processing facilities. Its rack-based architecture, deterministic scan cycle, and IEC 61131-3 compliance made it a standard-bearer for safety-adjacent automation in the late 1990s through the 2010s. Installed base remains significant across Asia-Pacific, the Middle East, and Eastern Europe, where long-lifecycle plant operations demand continued spare parts availability well beyond the platform's active production window.

The Evolution of MasterLogic Architecture

The MasterLogic platform was introduced by Honeywell as a mid-range PLC targeting process industries requiring high-availability redundancy without the full cost overhead of a DCS. The ML-200 series established a dual-rack redundancy model, with the 2MLR-CPUH/F-CC representing the hot-standby CPU variant designed for fault-tolerant configurations. Early revisions used proprietary backplane communication at fixed baud rates; later firmware revisions introduced enhanced diagnostics and expanded memory addressing to accommodate larger ladder and function block programs.

The platform's communication architecture evolved from RS-232/RS-485 serial links to Ethernet-based connectivity via dedicated communication modules, enabling integration with SCADA systems and Honeywell's own Experion PKS environment. Compatibility constraints exist between early-revision CPUs and later I/O expansion modules — specifically, firmware versions below 3.x on the CPUH variants do not support the extended analog I/O addressing introduced in the 2MLR-AIO series. Plants operating mixed-revision racks must validate firmware compatibility before substituting modules.

As the ML-200 has entered its end-of-active-support phase, Honeywell's recommended migration path is toward the ControlEdge PLC platform. However, the capital cost and engineering effort of full migration means the majority of installed ML-200 systems will remain in service through the 2030s, sustaining demand for original spare modules and tested refurbished units.

MasterLogic-200 Full Catalog & Functionalities (SKU List)

CPU & Controller Modules

• 2MLR-CPUH/F-CC: Hot-standby redundant CPU module, MasterLogic-200, fault-tolerant rack configuration
• 2MLR-CPUH/F: Standard hot-standby CPU, non-CC variant, primary/backup redundancy
• 2MLR-CPU1/F: Single CPU module, non-redundant configuration, standard processing
• 2MLR-CPU2/F: Enhanced single CPU, extended memory, faster scan cycle

Digital Input (DI) Modules

• 2MLR-DI16A: 16-channel 24VDC digital input module, sink/source configurable
• 2MLR-DI16B: 16-channel 120VAC digital input, isolated, panel-mount rack
• 2MLR-DI32A: 32-channel 24VDC digital input, high-density I/O expansion
• 2MLR-DI8A: 8-channel 24VDC digital input, individually isolated channels

Digital Output (DO) Modules

• 2MLR-DO16A: 16-channel 24VDC transistor output, 0.5A per channel
• 2MLR-DO16B: 16-channel relay output, 2A per channel, AC/DC load
• 2MLR-DO32A: 32-channel 24VDC transistor output, high-density configuration

Analog I/O Modules

• 2MLR-AI8A: 8-channel analog input, 4–20mA / 0–10V selectable, 12-bit resolution
• 2MLR-AO4A: 4-channel analog output, 4–20mA, 12-bit DAC, loop-powered
• 2MLR-AIO8A: 8-channel mixed analog I/O, configurable per channel

Communication & Network Modules

• 2MLR-ECOM: Ethernet communication module, 10/100 Mbps, Modbus TCP / proprietary ML protocol
• 2MLR-DCOM: DeviceNet communication adapter, scanner mode, up to 64 nodes
• 2MLR-PCOM: PROFIBUS-DP master/slave communication module

Power Supply Modules

• 2MLR-PS24: 24VDC rack power supply, 10A output, redundancy-capable
• 2MLR-PS120: 120VAC input power supply module, internal rack bus feed