Description
System Role and Integration
The 5X00121G01 serves as the personality-defining interface within the Ovation RTD input module architecture, functioning as the critical companion to the 5X00119G01 Electronics Module (EMOD). As a Personality Module (PMOD), it mounts directly with the EMOD in standard Ovation I/O bases to create a complete 8-channel resistance temperature detector input solution. While the EMOD provides the analog-to-digital conversion, logic processing, and communication functions, the 5X00121G01 supplies the essential signal conditioning, sensor-specific configuration, and field termination infrastructure.
This modular separation allows the same electronics platform (5X00119G01) to serve diverse RTD applications through appropriate personality module selection. The 5X00121G01 specifically configures the input channels for standard industrial RTD types—including platinum (Pt100, Pt200, Pt500), copper (Cu50, Cu53), and nickel (Ni120) elements—establishing the excitation currents, resistance ranges, and linearization curves required for accurate temperature conversion.
Core Functionality and Signal Handling
The module provides the physical interface between field-mounted RTD sensors and the measurement electronics, accommodating 2-wire, 3-wire, and 4-wire connection configurations to compensate for lead wire resistance errors. It houses the precision reference resistors and switching networks that enable the EMOD to perform lead wire compensation measurements in 3-wire mode, effectively eliminating measurement errors caused by long cable runs between the control room and field sensors.
Each of the eight channels is electrically isolated from the others and from the controller logic (via the mated EMOD), preventing ground loop currents from affecting measurement accuracy when multiple sensors reference different ground potentials. The module receives the low-level resistance signals from the RTD elements and conditions them for digitization by the EMOD’s 12-bit ADC, ensuring 0.10% accuracy at reference temperature across the supported sensor ranges.
Platform Heritage and Operational Benefits
Manufactured originally by Westinghouse and now maintained within Emerson’s Ovation portfolio, the 5X00121G01 represents the mature PMOD/EMOD architecture that enables flexible I/O configuration without specialized electronics for every sensor type. This design philosophy reduces spare parts inventory requirements—facilities stock the universal 5X00119G01 EMOD and specific personality modules (like the 5X00121G01 for RTDs, or 1C31116 series for thermocouples) rather than dedicated electronics for each input type.
The module is specifically designated as NOT compatible with CE Mark certified systems, indicating it is intended for legacy or non-European installations where specific EMC compliance markings are not required. This distinction is critical for procurement engineers specifying replacement parts, as CE-marked Ovation systems require alternative personality module variants to maintain compliance certifications.
WESTINGHOUSE 5X00121G01
Part 4: Technical Specifications
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Model Number: 5X00121G01
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Manufacturer: Westinghouse Electric Corporation (Emerson Ovation product line)
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Product Type: RTD Input Personality Module (PMOD)
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Compatible Electronics Module: 5X00119G01 (8-Channel RTD Input EMOD)
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Number of Channels: 8 (matches corresponding EMOD channels)
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Supported RTD Types: Platinum (Pt100, Pt200, Pt500), Copper (Cu50, Cu53), Nickel (Ni120)
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Wiring Configurations: 2-wire, 3-wire, 4-wire sensor connections
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Input Ranges: Configuration-dependent per RTD type (resistance ranges vary by sensor)
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Signal Conditioning: Lead wire compensation networks, excitation current distribution, precision reference resistors
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Isolation: Channel-to-channel and channel-to-logic isolation provided via mated EMOD (1000V AC/DC)
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Excitation Method: Current source excitation for RTD elements (sourced from EMOD)
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CE Mark Status: NOT compatible with CE Mark certified systems
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Operating Temperature: 0°C to 60°C (32°F to 140°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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Dimensions (Approximate): 12 cm × 3 cm × 9.5 cm (4.7 in × 1.2 in × 3.7 in)
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Weight: 0.1 kg to 0.8 kg (0.22 lbs to 1.76 lbs) depending on packaging
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Mounting: Plugs into Ovation I/O base in conjunction with 5X00119G01 EMOD
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Approvals: Standard industrial grade (non-CE variant)
Part 5: Core Features & Customer Value
Sensor Type Flexibility: The module’s support for multiple RTD types (platinum, copper, nickel) and resistance ranges allows facilities to standardize on a single electronics spare inventory (the 5X00119G01 EMOD) while deploying personality modules matched to specific field sensors. For maintenance managers, this reduces stocking costs and eliminatеs the risk of having obsolete specialized cards for rare sensor types—simply stock the universal EMOD and appropriate personality modules for the installed sensor base.
Lead Wire Compensation: The integrated support for 3-wire and 4-wire configurations enables automatic compensation for lead wire resistance, critical for accurate temperature measurement when sensors are located hundreds of feet from the I/O cabinet in large power plants or sprawling industrial sites. Engineers can run economical 3-wire RTD cables to remote field sensors without sacrificing measurement accuracy, avoiding the cost of 4-wire installations while maintaining precision better than ±0.2°C in most applications.
Modular Field Replacement: The PMOD/EMOD separation allows field technicians to replace the personality module independently of the electronics module during sensor type changes or hardware failures. If an RTD input channel fails due to personality module component damage, technicians can swap the 5X00121G01 without disturbing the EMOD configuration or field wiring terminations, reducing mean time to repair (MTTR) and minimizing exposure of sensitive electronics to static discharge during maintenance.
Galvanic Isolation Architecture: While the personality module itself provides the field termination, the isolation barrier is completed through the mated EMOD, providing 1000V AC/DC separation between field sensor wiring and controller logic. This isolation prevents ground loop currents from inducing measurement errors when multiple RTDs reference different equipment grounds—a common issue in power plant environments where sensor grounding may vary between turbine bearing housings, heat exchangers, and piping systems.
WESTINGHOUSE 5X00121G01
Part 6: Typical Applications
Power Generation Steam Temperature Monitoring: The 5X00121G01 is extensively deployed in coal-fired, gas-fired, and nuclear power plants for monitoring main steam temperature, superheated steam temperature, and turbine metal temperatures. When paired with the 5X00119G01 EMOD, it provides the Pt100 sensor configuration required for high-temperature steam measurements (up to 600°C), enabling precise control of attemperator spray valves and turbine thermal stress monitoring systems critical for unit life extension.
Turbine Bearing Temperature Supervision: Within steam and gas turbine generator sets, the module monitors bearing pad temperatures, thrust bearing wear indicators, and generator winding temperatures using Pt100 or Cu50 RTDs embedded in the bearing housings. The 3-wire lead compensation capability proves essential for turbine applications where sensor cables run through harsh turbine hall environments with potential for ground potential differences between the bearing housing and the control cabinet ground reference.
Chemical Reactor Temperature Control: In petrochemical and specialty chemical plants, the module provides temperature input for exothermic reaction vessels, distillation column reboilers, and catalyst bed monitoring. The flexibility to configure Cu50 sensors for cryogenic applications (-200°C) or Pt500 sensors for high-temperature processes (up to 850°C) through the same personality module allows chemical engineers to standardize on a single I/O card type across diverse process units.
HVAC and Environmental Control: In large central utility plants and data center cooling systems, the 5X00121G01 configures the 5X00119G01 EMOD to monitor chilled water supply/return temperatures, cooling tower basin temperatures, and air handling unit discharge temperatures using Ni120 or Pt100 sensors. The 2-wire configuration support accommodates economical temperature transmitters in non-critical comfort applications while maintaining sufficient accuracy for energy optimization algorithms.
