Honeywell 2MLI-CPUH Retrofit-Ready CPU for Experion PKS Control Systems
The Honeywell 2MLI-CPUH is a high-performance DCS CPU module engineered for the Experion PKS (Process Knowledge System) platform. Designed to serve as a direct retrofit replacement for aging or discontinued controller hardware, this module enables industrial facilities to modernize their distributed control architecture without requiring a full system overhaul. Whether you are managing a refinery, chemical plant, power generation facility, or continuous process operation, the 2MLI-CPUH provides a reliable, specification-matched upgrade path that preserves existing I/O wiring, backplane connections, and control logic.
For engineers and maintenance teams undertaking a legacy system migration, the 2MLI-CPUH slots into the standard Experion PKS chassis and communicates natively over the FTE (Fault Tolerant Ethernet) network backbone. This means existing C300 Controller configurations, CHARM I/O modules, and Series C I/O links remain fully compatible without requiring re-engineering of the field wiring or control cabinet layout. The module supports redundant CPU configurations, allowing hot-standby failover to be maintained throughout the retrofit process — a critical requirement for facilities that cannot tolerate unplanned shutdowns.
Upgrade Compatibility Table
| Parameter | Details |
|---|---|
| Compatible Platform | Honeywell Experion PKS (C300, Series C) |
| Backplane Interface | Standard Experion PKS chassis backplane |
| Communication Protocol | FTE (Fault Tolerant Ethernet), OPC, Modbus TCP |
| Redundancy Support | Hot-standby CPU redundancy supported |
| I/O Compatibility | CHARM I/O, Series C I/O, Remote I/O links |
| Installation Requirement | Standard DIN rail / chassis slot mounting |
| Replacement Recommendation | Direct drop-in for discontinued Experion PKS CPU variants |
| Commissioning Note | Verify module address, firmware revision, and FTE node ID before power-on |
| Warranty | 12-Month Warranty — tested and verified before shipment |
Retrofit Planning for Existing Automation Systems
A successful retrofit begins well before the replacement module arrives on site. When planning a 2MLI-CPUH installation, the engineering team should first audit the existing Experion PKS chassis to confirm available slot positions and backplane power budget. The PM IO Link module and associated CHARM I/O assemblies must be inventoried to ensure address mapping is preserved after the CPU swap. In many legacy installations, the power supply module — typically a Honeywell PS-ACDC or equivalent — must be evaluated for capacity, as newer CPU modules may draw marginally different current profiles.
Terminal block wiring on the Series C I/O modules should be documented with as-built drawings before any hardware is removed. Field signals connected through CHARM CHARacterization Modules retain their wiring during a CPU-only swap, but the engineer must confirm that the CHARM I/O base addresses are correctly reflected in the Control Builder application database. If the facility is also migrating from an older Experion R310 or R400 release to a current R501 or later version, the Control Builder project file must be exported, validated, and re-imported after the CPU replacement to ensure function block compatibility.
Communication links to third-party systems — including Modbus RTU devices connected through a Honeywell HC900 gateway, PROFIBUS DP field instruments, or OPC DA/UA historian connections — should be tested in simulation mode before the live cutover. The FTE switch configuration and node IP assignments must be verified to avoid duplicate address conflicts on the control network. HMI screens built in Experion Station or third-party SCADA platforms referencing tag names from the C300 Controller database will continue to function without modification, provided the tag database is exported and re-loaded correctly into the replacement CPU.
For facilities running redundant CPU pairs, the recommended procedure is to replace the standby CPU first, allow it to synchronize with the primary, then perform a controlled switchover before replacing the original primary unit. This approach eliminates unplanned downtime and allows the control system to remain in automatic mode throughout the hardware exchange. Programming cables and the Experion PKS Engineering Station should be on-site during the cutover to support any real-time diagnostics or parameter adjustments required during commissioning.
Downtime Control During System Migration
Minimizing production interruption during a DCS CPU retrofit requires a structured change management approach. The 2MLI-CPUH supports online firmware loading and redundancy synchronization, which means the replacement can be staged during normal production without requiring a full system shutdown. Prior to the physical swap, the existing CPU’s configuration checkpoint should be saved to the Experion PKS server and backed up to an offline engineering workstation.
During the cutover window, the control system should be placed in manual mode for critical loops, with field operators stationed at key process areas to monitor analog outputs and valve positions. Once the 2MLI-CPUH is installed and powered, the module will perform a self-diagnostic sequence and attempt to load its configuration from the Experion server. The engineer should monitor the System Status Display in Experion Station to confirm that all I/O points return to scan, all CHARM modules report healthy, and all FTE links re-establish within the expected timeframe — typically under five minutes for a well-prepared cutover.
Post-installation, a full I/O loop check is recommended to verify that field signals are reading correctly and that control outputs are responding as expected. Any discrepancies in analog scaling, PID tuning parameters, or alarm setpoints should be corrected before returning loops to automatic. The 12-month warranty on the 2MLI-CPUH covers hardware defects identified during this commissioning phase, and SMARTNEXMSK provides pre-shipment functional testing documentation upon request.
Retrofit Support FAQ
Q: Is the 2MLI-CPUH a direct drop-in replacement for my existing Experion PKS CPU?
A: In most Experion PKS chassis configurations, yes. The 2MLI-CPUH is designed to occupy the standard CPU slot and communicate over the existing FTE backplane. You should verify the chassis revision and firmware compatibility with your Experion PKS release version before installation.
Q: Do I need to re-wire my I/O terminals when replacing the CPU module?
A: No. A CPU-only swap does not require changes to field wiring on CHARM I/O or Series C I/O modules. Terminal block connections remain undisturbed. Only the CPU slot hardware is exchanged.
Q: How do I confirm communication compatibility with my existing SCADA and historian systems?
A: Verify that the FTE node ID and OPC server tag paths are preserved in the replacement CPU configuration. If your historian uses OPC DA connections to the Experion server, those connections are maintained at the server level and are not affected by the CPU hardware swap.
Q: What does the 12-month warranty cover?
A: The warranty covers hardware defects under normal operating conditions. Each unit undergoes functional testing prior to shipment. Test reports are available upon request. Contact our team for RMA procedures if a defect is identified within the warranty period.
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