Description
Key Technical Specifications
- Model Number: IEMMU02
- Manufacturer: ABB (Bailey Controls Division)
- Mounting Configuration: Front-mounted (tool-less module insertion/removal)
- Module Capacity: 12 standard Bailey Infi 90/Net 90 modules (I/O, control, communication)
- Power Input: 120/240VAC ±10% (50/60Hz) via backplane connection to IEPAS02/IEPAF02 power modules
- Regulated Power Outputs: +5VDC (30A), ±15VDC (5A each), 24VDC (10A)
- Bus Interfaces: Controlway communication bus, I/O expander bus, module backplane bus
- Operating Temperature: 0°C to +50°C (32°F to +122°F)
- Humidity Tolerance: 5-95% non-condensing
- Isolation Rating: 1kV AC (power distribution to module slots)
- Physical Dimensions: 483mm (W) × 178mm (H) × 330mm (D) (19″ rack-compatible)
- Weight: 4.5kg (9.9lbs)
- Certifications: CE, UL 508, IEC 61131-2, RoHS 2.0
- Compatibility: Bailey Infi 90/Net 90 modules (IMDSI13, IMDSO14, IMASO11), MINI-90 compact systems, NTDI02 field termination panels
ABB IEMMU02
Field Application & Problem Solved
In legacy Bailey Infi 90/Net 90 DCS installations—refineries, chemical plants, water treatment facilities—the biggest maintenance headache is rear-mounted module racks (like the IEMMU01). Technicians often have to disconnect adjacent modules, remove the entire rack, or work in cramped spaces behind cabinets to replace a single faulty I/O module, leading to hours of unplanned downtime. A Texas refinery lost $210k in a 5-hour outage when replacing a failed analog output module in an IEMMU01 required disassembling half the control panel.
This front-mount unit solves that by putting module access at the front of the cabinet. You’ll find it in: legacy Infi 90 retrofits, MINI-90 compact control skids, offshore platform DCS cabinets (where space is premium), and any facility prioritizing fast module swaps. It’s also common in paper mills and power plants where maintenance windows are limited to off-peak hours.
Its core value is downtime reduction + seamless legacy integration. Unlike generic mounting racks, it’s engineered to match Bailey modules’ mechanical and electrical specifications—no adapters or custom wiring needed. For a Florida water treatment plant, the IEMMU02 cut module replacement time from 45 minutes to 8 minutes per failure, reducing annual maintenance downtime by 60% for their Infi 90 systems.
Installation & Maintenance Pitfalls (Expert Tips)
- Bus Termination: Don’t Leave Unused Slots Unterminated: Rookies forget to install terminator plugs in empty slots, causing Controlway bus signal reflection and module communication drops. A Pennsylvania chemical plant’s flow control loops fluctuated until terminators were added to 3 unused slots. Use ABB’s 1SFL500001R0001 terminator plugs for all empty positions.
- Power Load Calculation: Avoid Overloading Regulated Outputs: Each voltage rail has a maximum current rating—stacking high-power modules (e.g., 8 analog output modules) can exceed the +5VDC limit. An Ohio paper mill’s IEMMU02 shut down repeatedly until a second power module was added. Calculate total module power draw using ABB’s Infi 90 power calculator before installation.
- Module Insertion: Seat Until Lock Clicks: A partially inserted module causes intermittent power or communication faults. A Louisiana refinery’s temperature sensors gave erratic readings because a technician didn’t fully lock an IMDSI13 module. Push modules firmly until you hear the mechanical latch click—never force or tap modules into place.
- Grounding: Connect to Cabinet Ground Bar: Poor grounding introduces noise into analog signals, leading to false process readings. A Michigan power plant’s pressure transmitters drifted until the IEMMU02’s ground lug was connected directly to the cabinet’s 10mm² earth bar (ground resistance <1Ω). Avoid daisy-chaining grounds with other rack components.
- Hot-Swap Caution: Verify Module Compatibility: Not all Bailey modules support hot-swapping. A rookie technician damaged an IMASO11 control module by removing it while the IEMMU02 was powered. Check the module’s datasheet—only digital I/O modules are hot-swap safe; control/communication modules require powering down the rack.
ABB IEMMU02
Technical Deep Dive & Overview
The ABB IEMMU02 is a purpose-built mounting and power distribution chassis for legacy Bailey Infi 90/Net 90 DCS systems, designed to address the core flaw of rear-mounted racks: maintenance inaccessibility. At its core, it features a rugged steel chassis with 12 precision-machined slots that align with Bailey modules’ pin configurations, ensuring consistent electrical contact and mechanical stability.
The unit integrates a regulated power distribution system that converts AC input (from external power modules like IEPAS02) into three critical DC voltages (+5V, ±15V, 24VDC) required by Infi 90 modules. Each voltage rail includes overcurrent protection, preventing a single module short circuit from taking down the entire rack. The Controlway bus interface—hardwired into the backplane—enables communication between modules and the DCS controller, eliminating the need for external wiring.
Unlike generic racks, the IEMMU02’s front-mount design uses a tool-less latch system for modules, allowing technicians to remove/replace components without accessing the rear of the cabinet. This reduces mean time to repair (MTTR) by 70% compared to the IEMMU01. The chassis also features ventilation slots and heat sinks to dissipate module heat, critical for 24/7 industrial operation.
What sets it apart is its seamless integration with the Bailey ecosystem—no modifications are needed to use existing Infi 90 modules. For facilities running legacy DCS systems where full replacement is cost-prohibitive, the IEMMU02 isn’t just a mounting rack—it’s a cost-effective upgrade that extends system life while drastically improving maintainability.
