Description
System Role and Integration
The 3A99266G01 serves as the critical interface bridge within the Ovation Distributed Control System architecture, functioning as a Local Input/Output Transition Panel (LIOTP) that connects distributed controller nodes to field-mounted I/O devices. As a transition assembly, it mounts within Ovation control cabinets and provides the necessary physical infrastructure for routing signals between the controller backplane and local I/O modules, ensuring reliable communication pathways for process data acquisition and control output distribution.
This module occupies a foundational position in the Ovation I/O hierarchy, typically installed in expansion cabinets or local I/O stations where it aggregates connections from multiple I/O branches. Unlike active signal processing modules that perform A/D conversion or logic functions, the 3A99266G01 provides the passive connectivity and signal conditioning infrastructure required to interface various I/O card types—analog inputs, discrete outputs, relay modules, and specialty interfaces—with the central controller processor.
Core Functionality and Signal Handling
The panel provides organized terminal blocks and internal bus connections that route field wiring from process sensors and final control elements to the appropriate I/O modules within the Ovation chassis. It manages the physical transition between external field cabling (typically shielded twisted pair or multi-conductor cables) and the internal backplane connections of the Ovation I/O branches, ensuring proper signal integrity through maintained grounding and shield continuity.
The 3A99266G01 supports the integration of up to four I/O branches per expansion cabinet configuration, accommodating up to 32 individual I/O modules (eight modules per branch) in a typical setup. The panel includes provisions for power distribution to local I/O modules, with 24VDC auxiliary power routing to support field device excitation and module electronics. Signal conditioning components on the PC board assembly provide basic filtering and transient protection to safeguard sensitive controller electronics from field-side electrical disturbances.
Platform Heritage and Operational Benefits
As a component of the Westinghouse Ovation platform now maintained within Emerson’s automation portfolio, the 3A99266G01 reflects the modular, distributed I/O philosophy that enables Ovation systems to scale from small unit controls to large plant-wide distributed architectures. The transition panel design allows engineers to locate I/O modules close to field devices—reducing wiring runs, installation costs, and signal degradation—while maintaining seamless integration with the central control network.
The ruggedized PC board construction utilizes industrial-grade components rated for harsh environments, including extended temperature ranges and high-vibration conditions typical of power generation turbine halls and petrochemical process units. The compact form factor optimizes cabinet space utilization, allowing high-density I/O configurations without requiring excessive enclosure real estate. Integration with standard Ovation power distribution modules and DIN rail mounting systems facilitates rapid installation and maintenance.
3A99266G01
Part 4: Technical Specifications
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Model Number: 3A99266G01
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Manufacturer: Westinghouse Electric Corporation (Emerson Ovation product line)
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Product Type: Local Input/Output Transition Panel (LIOTP) / PC Board Assembly
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Function: I/O signal transition and distribution interface
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Power Supply: 24 VDC (auxiliary power for I/O module support)
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Power Consumption: Approximately 20W
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Operating Temperature: -40°C to +70°C (-40°F to +158°F)
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Storage Temperature: -40°C to +85°C (-40°F to +185°F)
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Humidity: 0% to 95% RH (non-condensing)
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Vibration: 5g RMS, 10 to 500 Hz
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Shock: 30g, 11 ms half-sine
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I/O Capacity: Supports up to 4 I/O branches (32 I/O modules typical)
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Mounting: Panel mount or DIN rail compatible within Ovation enclosures
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Field Termination: Screw terminal blocks for field wiring
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Dimensions: Approximately 25.4 cm × 7.0 cm × 2.5 cm (10.0 in × 2.8 in × 1.0 in)
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Weight: 0.7 kg to 1.0 kg (1.5 lbs to 2.2 lbs) depending on configuration
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Protection Class: IP20 (control cabinet installation)
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Construction: Ruggedized PC board with industrial-grade components
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Status: Discontinued by manufacturer (available via secondary market)
Part 5: Core Features & Customer Value
Modular I/O Expansion Capability: The transition panel enables distributed I/O architecture by providing the physical interface for remote I/O cabinets located near field equipment. For large-scale power plants and process facilities, this eliminates the need for extensive multi-conductor cable runs back to a central control room, reducing installation costs by 30-50% compared to traditional centralized I/O architectures while improving signal integrity by shortening analog cable lengths.
Ruggedized Industrial Construction: Built to withstand the vibration, temperature extremes, and electrical noise characteristic of turbine halls, compressor stations, and outdoor process skids, the panel ensures continuous operation in environments where consumer-grade electronics would fail. The -40°C to +70°C operating range accommodates installations in uncontrolled outdoor enclosures or extreme climate conditions without requiring auxiliary heating or cooling.
Simplified Field Wiring Infrastructure: The organized terminal block layout and internal bus architecture streamline the connection of field devices to Ovation I/O modules, reducing commissioning time and wiring errors. For maintenance technicians, the clear physical separation between field wiring (bottom entry) and controller connections (backplane interface) facilitates troubleshooting and hot-swapping of I/O modules without disturbing field terminations.
High-Density Space Optimization: The compact form factor maximizes I/O density within standard Ovation control cabinets, allowing up to 32 I/O modules per expansion panel. This space efficiency proves critical in retrofit applications where existing control room real estate is limited, enabling modernization of legacy systems without requiring additional building expansion or cabinet footprint increases.
System Integration Standardization: As an official Ovation component, the panel maintains full compatibility with Ovation power distribution modules, controller chassis, and communication networks. This standardization ensures that spare parts are interchangeable across multiple units and sites, reducing inventory complexity and ensuring that expansion projects integrate seamlessly with existing Ovation infrastructure without custom engineering.
3A99266G01
Part 6: Typical Applications
Power Generation Expansion Cabinets: The 3A99266G01 is extensively deployed in coal-fired, gas-fired, and nuclear power plants as the local I/O interface for expansion cabinets located near turbine auxiliaries, boiler feed pumps, and balance-of-plant equipment. In these applications, the panel aggregates inputs from vibration sensors, temperature transmitters, and pressure switches located in the turbine hall, providing the transition wiring to Ovation analog and discrete input modules while maintaining signal isolation from high-voltage switchyard transients.
Water Treatment Distributed I/O: In municipal and industrial water treatment facilities, the panel serves as the local I/O hub for remote pump stations and filter skids. It interfaces with flow meters, level switches, and chemical feed pumps located hundreds of feet from the main control room, allowing the Ovation system to extend distributed control to remote well fields and reservoir pumping stations without requiring dedicated controller nodes at each location.
Petrochemical Process Units: Within refinery and chemical processing plants, the transition panel provides the physical infrastructure for I/O cabinets distributed throughout process units such as distillation columns, reactor vessels, and compressor stations. The panel handles the interface between field-mounted smart transmitters and Ovation HART I/O modules, enabling asset management integration while withstanding the corrosive atmospheres and temperature extremes common in refining environments.
Pipeline and Compression Facilities: In natural gas pipeline applications, the panel facilitates the deployment of Ovation control systems at remote compressor stations and metering facilities. The ruggedized construction tolerates the vibration of gas turbine compressors and the temperature cycling of outdoor enclosures, while the 24VDC power distribution supports local instrumentation without requiring separate power engineering for each remote site.
Pulp and Paper Mill Controls: The module finds application in paper machine control cabinets and pulping process areas, providing the I/O transition for machine speed controls, stock flow valves, and drying section temperature loops. The high shock and vibration ratings accommodate the mechanical pulsations of paper machines and pulp refiners while maintaining precise analog signal integrity for quality control loops.
