Description

The METSO IOP351 is a high-performance, multi-variable pressure transmitter designed for advanced process measurement applications requiring comprehensive process parameter monitoring. As a sophisticated member of Metso’s (now part of Neles/Valmet) instrumentation portfolio, this device represents a significant evolution beyond traditional pressure transmitters by simultaneously measuring multiple process variables. The core function of the IOP351 is to accurately measure differential pressure, static line pressure, and process temperature using integrated sensors, calculating and transmitting derived values such as mass flow, energy flow, and density. This multi-variable capability is transmitted via digital fieldbus protocols like Foundation Fieldbus or Profibus PA, providing a rich dataset to the control system from a single instrument point, thereby reducing installation complexity and improving measurement accuracy through integrated compensation.

The IOP351 delivers exceptional value in applications where process conditions vary significantly, as it automatically compensates for changes in temperature and pressure that would affect the accuracy of a conventional differential pressure-based flow measurement. Its integrated design eliminates the need for separate pressure and temperature transmitters, reducing potential measurement errors caused by installation differences between separate devices. The transmitter is engineered for critical measurement points in custody transfer, energy monitoring, and process optimization where measurement uncertainty must be minimized. The METSO IOP351 combines advanced sensor technology with powerful computing capabilities to provide a comprehensive process variable solution, making it an ideal choice for demanding applications in oil and gas, chemical processing, and power generation where accurate compensated flow measurement is essential for operational efficiency and fiscal accountability.

IOP351 METSO

Technical Specifications

Parameter Name	Parameter Value
Product Model	IOP351
Manufacturer	METSO (Now Neles, part of Valmet)
Product Type	Multi-Variable Pressure Transmitter
Measured Variables	Differential Pressure, Static Pressure, Process Temperature
Differential Pressure Range	Selectable (e.g., 0-0.5 kPa to 0-3 MPa)
Static Pressure Range	High, typically 0-25 MPa
Temperature Range	-40°C to +125°C (via RTD sensor)
Output Signals	Foundation Fieldbus, Profibus PA, 4-20 mA HART
Accuracy (DP)	High, typically ±0.04% of calibrated span
Accuracy (Static P)	Typically ±0.1% of URL
Temperature Accuracy	Typically ±0.5°C
Process Connection	¼” NPT or flange connections for HP/LP sides
Diaphragm Material	316L Stainless Steel, Hastelloy C-276
Housing Material	Stainless steel with corrosion-resistant coating
Protection Class	IP66 / IP67 / Type 4X
Operating Temperature	-40°C to +85°C (electronics)
Power Supply	9-32 V DC (for fieldbus); 10.5-45 V DC (for HART)
Calculated Variables	Mass flow, energy flow, density, volume flow

Main Features and Advantages

The METSO IOP351 offers transformative advantages through its integrated multi-variable measurement capability. The most significant feature is the simultaneous measurement of differential pressure, static pressure, and process temperature from a single device, which enables real-time compensation of flow measurements for changing process conditions. This eliminates the measurement errors that occur when separate instruments are used for these variables, particularly improving accuracy in gas and steam flow applications where temperature and pressure significantly affect density. The IOP351 performs sophisticated calculations internally, providing directly usable process values like mass flow and energy flow without requiring additional computing resources in the control system.

The transmitter incorporates advanced diagnostics that monitor all three measurement elements and the overall health of the device, providing predictive maintenance alerts and detailed status information. The digital communication capabilities allow for extensive configuration flexibility, remote calibration verification, and access to comprehensive process data beyond what conventional 4-20 mA instruments can provide. The robust sensor design ensures excellent long-term stability across all measured variables, reducing maintenance requirements and calibration frequency. The integration of temperature measurement within the pressure sensor assembly ensures perfect synchronization of measurements, critical for accurate compensation calculations. The combination of multiple measurement capabilities, digital intelligence, and robust construction makes the IOP351 a comprehensive solution that reduces installation costs, improves measurement accuracy, and enhances process visibility compared to traditional separate-instrument approaches.

Application Field

The METSO IOP351 finds critical application in industries where accurate compensated flow measurement directly impacts operational efficiency, safety, and financial performance. In oil and gas production, it is essential for custody transfer of natural gas, where accurate mass flow measurement is legally and financially critical, and for flare gas monitoring where precise measurement is required for regulatory compliance. Refineries utilize the IOP351 for critical process flow measurements where temperature and pressure compensation is necessary for mass balance calculations and process optimization. Chemical processing plants employ this transmitter for reactor feed control, energy balance monitoring, and batching operations where density variations affect product quality.

In power generation, the IOP351 provides accurate steam flow measurement for turbine efficiency monitoring and heat rate calculations, with automatic compensation for temperature and pressure variations. District energy systems use these transmitters for energy billing based on actual energy content of steam or hot water. The pharmaceutical and food industries benefit from the IOP351‘s accurate mass flow measurement for recipe control and batch consistency. Essentially, any application involving gas, steam, or liquid flow where temperature and pressure significantly affect density represents an ideal application for the IOP351, particularly when measurement accuracy has safety, quality, or financial implications that justify the investment in advanced instrumentation.

IOP351 METSO

Related Products

IOP352: A similar multi-variable transmitter with potentially different communication protocols or performance specifications.

IOP302/303: Standard differential pressure transmitters for applications not requiring multi-variable capability.

Remote Seal Kits: Specialized seal assemblies for use with the IOP351 in challenging media applications.

Flow Computing Modules: Additional computing resources for complex flow calculations beyond the transmitter’s built-in capabilities.

Metso FieldCare: Advanced asset management software for configuration, calibration, and diagnostics of the IOP351.

Primary Flow Elements: Orifice plates, flow nozzles, and venturi tubes that create the differential pressure measured by the IOP351.

Fieldbus Infrastructure: Network components including power supplies, conditioners, and cabling for digital network installations.