Honeywell MLI Series Modules - MLI-DR64H/D1

Technical Dossier

Product Details And Specifications

Honeywell MLI Series Technical Notes

The Evolution of MLI Architecture

The MLI series was introduced as part of Honeywell's TDC 3000 and PlantScape ecosystem, designed to bridge legacy relay logic with modern digital control. Early-generation MLI modules operated on a proprietary Local Control Network (LCN) backplane, using parallel bus communication at fixed scan rates. Mid-generation revisions introduced enhanced diagnostics, redundancy support, and compatibility with Honeywell's Universal Control Network (UCN). Later variants added HART pass-through capability on analog modules and expanded the digital output density to 64 points per card (as seen in the MLI-DR64H/D1). Compatibility between early and late MLI generations requires careful backplane revision matching — specifically, modules rated for the H-series backplane (suffix /H or /D1) are not interchangeable with earlier B-series racks without firmware and termination assembly verification. As Honeywell has transitioned its DCS portfolio toward Experion PKS and C300 controllers, the MLI series has entered a mature/end-of-life phase. Honeywell no longer manufactures new MLI modules; all procurement is sourced through authorized repair depots or specialist spare parts distributors.

MLI Full Catalog & Functionalities (SKU List)

Digital Output Modules

• MLI-DR64H/D1: 64-channel 24VDC digital output, H-series backplane, D1 termination assembly
• MLI-DR32H: 32-channel 24VDC digital output, H-series rack, standard density
• MLI-DR16H: 16-channel relay digital output, H-series, isolated contact outputs
• MLI-DR64B: 64-channel digital output, B-series backplane, legacy variant

Digital Input Modules

• MLI-DI64H/D1: 64-channel 24VDC digital input, H-series backplane, D1 termination
• MLI-DI32H: 32-channel 24VDC digital input, H-series rack, standard density
• MLI-DI16H: 16-channel 120VAC digital input, H-series, high-voltage variant
• MLI-DI64B: 64-channel digital input, B-series backplane, legacy variant

Analog Output Modules

• MLI-AO16H: 16-channel 4–20mA analog output, H-series, loop-powered
• MLI-AO08H: 8-channel 4–20mA analog output, H-series, isolated outputs
• MLI-AO16B: 16-channel analog output, B-series backplane, legacy variant

Analog Input Modules

• MLI-AI16H: 16-channel 4–20mA/HART analog input, H-series, HART pass-through
• MLI-AI32H: 32-channel analog input, H-series, high-density process measurement
• MLI-AI16B: 16-channel analog input, B-series backplane, legacy variant

CPU & Controller Modules

• MLI-CPU01H: Primary logic controller, H-series, redundancy-capable, LCN/UCN interface
• MLI-CPU02H: Enhanced CPU with expanded memory, H-series, dual-port network

Power Supply Modules

• MLI-PS24H: 24VDC rack power supply, H-series, redundant input capable
• MLI-PS48H: 48VDC rack power supply, H-series, for high-current I/O racks

Communication Adapters

• MLI-NIM01: Network Interface Module, LCN bus adapter, primary node interface
• MLI-UCN01: Universal Control Network adapter, UCN-to-MLI rack bridge

Sourcing Hard-to-Find & Obsolete MLI Series Parts

Q: How are RFQ terms confirmed?
A: Quantity, required condition, documentation needs, destination and sourcing route are confirmed during RFQ review before quotation.

Quality Control for the MLI Range

Q: How is condition confirmed before quotation?
A: Available condition, photos, test records and documentation are checked according to the requested model and sourcing channel before a formal RFQ response.