Automated Measurement Systems and Process Control (PLC/SCADA)
Recommendations

On this page we present material for the development of measurement and control systems (PLC/SCADA) using the example of Oil & Gas Metering Stations. This is a shortened introductory version. The full version is available upon request. The full version represents a detailed manual on developing such systems — a real handbook for leading engineers. It will also be useful for managers, project leaders, technical and administrative executives.

1. Oil & Petroleum Products Measurement System. Definition, Application.

A metering system (СИКН) is a system for measuring quantity and determining the quality of oil and petroleum products. The system includes peripheral infrastructure and equipment, and all together it forms an Oil and Petroleum Products Metering Station.

The metering station ensures custody transfer measurement of crude oil and products at oil terminals, hubs, refineries and other facilities. For export commercial operations, the metering station is the main type of custody transfer measurement unit, classified under GOST R 8.595 and OIML R 117.

The metering system provides:

• Direct and indirect dynamic measurements of flow and quality;

• Recording and reporting in accordance with API MPMS and ISO/IEC 17025;

• Verification and calibration using reference equipment and provers.

The metering station is the core element of the North-West transit corridor, performed by SIA Olimps, with Pro meter specialists as part of the engineering team.

For engineers, the metering system is both a measurement system (flow, density, temperature, pressure, prover) and an infrastructure station (operator room, laboratory, electrical, cabling, prover water draw, service areas). These two levels must always be clearly separated: Metering System ≠ Metering Station.

For clients, Pro meter ensures that this difference is respected in contracts, designs and protocols. This is part of the Legal Shield.

2. Project life cycle: from idea to pilot operation and industrial operation

We show the schematic route: ToR → tender/competition → design → documentation → implementation → testing and primary verification → calibration/verification → pilot operation → industrial operation.
These stages will be further elaborated in a separate file for this page — “Development of automated metering and control systems” — available at /prometer/pro/engineering-full-pdf/.

Standards and best practices we rely on:

• API MPMS (measurement, proving and custody transfer standards)

• OIML R 117 (dynamic measurement of liquids for commercial transactions)

• MID (MI-005) (for application in the EU)

• ISO 5167 (flow devices), ISO 7066 (data processing), ISO/IEC 17025 (calibration/ laboratories)

• GOST R 8.595, GOST 8.586 and related national standards

• For automation and safety: IEC 61131 / IEC 61158 (PLC/fieldbus), IEC 61511 (SIS) — requirements for facilities.

The design logic at each stage is fixed in a compliance matrix — piping diagrams, methods and protocols — all of which are part of the Legal Shield framework.

3. Terms of Reference (ToR) and FEED: structure and requirements for accuracy

The Terms of Reference (ToR) for the creation of a metering unit / system for measuring the quantity of oil or an automated control system (PLC/SCADA) is usually provided in tenders, government and commercial proposals by the Customer as an initial ToR.

Further, Pro meter, together with tender documents, proposes its own template of ToR for subsequent work with the Customer, suppliers and other interested parties. The template takes into account more complete technical conditions, requirements of the regulatory framework and complies with Legal Shield. At this stage we often propose new technical solutions.

After signing the contract for project implementation, Pro meter studies the Customer’s ToR and other technical documentation, proposes main technical solutions, and together with suppliers and the Customer’s engineers, develops the ToR for the implementation of the project, including the section Metrological Support.

What the ToR from Pro meter includes (main parts):

• Technological regulation: detailed description of processes; combined single-line technological diagram with schematic automation.

• Recommendations for the construction part (even if not provided for in the contract).

• Recommendations on process technology.

• Recommendations for the IT department, including calculation algorithms and control of the process (PLC/SCADA/LIMS).

• Recommendations for the chief power engineer: reserve power supply, fast emergency switching, requirements for safety and reliability.

• Recommendations on safety and ecology.

• Preliminary (before pilot operation) operating instructions.

Regulatory framework (as a reference), on which the ToR relies:

• API MPMS, OIML R117, MID (MI-005);

• ISO 5167, ISO 7066, ISO/IEC 17025;

• GOST R 8.595, GOST 8.586 and related national standards;

• For automation and safety: IEC 61131, IEC 61158 (PLC/fieldbus), IEC 61511.

Outputs of ToR/FEED: list of accepted standards, P&ID, specification of measuring instruments (working/standard), requirements for auxiliary systems, interfaces with PLC/SCADA/LIMS, formats of reports and protocols, FAT/SAT and verification methodology — all of which are included in the Legal Shield of the project.

The full detailed template of the Terms of Reference is in the document “Guidelines for the development of measurement systems, automated control systems of measurement and PLC/SCADA. Recommendations”. Link to this document. 

4. Development and Design

This stage of the project is divided into conceptual, draft, plant and regional projects. We unite four main engineering activities into one structure and complete them in one working package.

1) Basic conceptual project.

At this stage, the Customer forms requirements for the metering unit in tenders. Pro meter, based on engineering experience, proposes its conceptual solutions, taking into account international standards and the requirements of Custody Transfer. The output of the conceptual project is a preliminary concept of the metering system with schematic solutions.

2) Draft project by the Customer.

The Customer issues initial requirements in the form of a ToR or tender proposals. Pro meter prepares its draft project with schematic diagrams, technological solutions, taking into account the site conditions and the Customer’s choice of equipment.

3) Plant project.

A plant project is developed taking into account the participation of the manufacturer and the regional engineering company. Pro meter specialists (together with Olimps) prepare a full set of design documentation, including P&ID diagrams, specifications and calculations. The plant project is the main package for expert review and approval.

4) Regional project (project of adaptation, technical project).

A regional project is developed jointly with the regional engineering company — SIA Olimps (Latvia). Together with the manufacturer’s documentation, Pro meter prepares a regional project taking into account local regulatory requirements, safety, and installation conditions. This allows the project to be included in the official documentation package and implemented directly on the site.

Engineering link “plant – regional”: how we align standards and deadlines

At this stage it is important not only to follow international standards and Customer requirements, but also to harmonize them with local legislation and safety requirements.

What is included in the project (Standards Mapping):

• Compliance with API MPMS, OIML R117, ISO/IEC 17025, ASTM, GOST, MID (MI-005).

• Requirements of local legislation: construction norms, occupational safety, ecology.

• Mapping international and local requirements into one matrix, which Pro meter includes in the project documentation and Legal Shield package.

Pro meter guarantees that what is included in the project is not only checked and verified, but also legally protected: contracts, agreements, tender conditions and acceptance certificates are checked, errors and risks are eliminated in advance. This is how the Legal Shield works in practice.

How documentation is formed

• Complete project package (conceptual + draft + plant + regional).

• ToR, P&ID diagrams, FAT/SAT checklists, Acceptance Criteria, protocols.

• For software and automation: PLC/SCADA/LIMS algorithms, operator interfaces, OPC UA integration.

• For metrology: methodology of proving, calibration, verification.

• For ecology and safety: instructions, risk analysis, accident prevention.

• For commissioning: preliminary and final instructions, operating logs.

Output of the design stage:

• Standard Mapping Matrix — one document uniting international and local standards.

• Complete project package with drawings and specifications.

• Documentation for FAT/SAT and pilot operation.

• All protocols are included in the Legal Shield of the project.

Normative base used in the project:

• API MPMS 2019, OIML R117, MID (MI-005).

• ISO 5167, ISO 7066, ISO/IEC 17025.

• GOST R 8.595, GOST 8.586, related national standards.

• IEC 61131, IEC 61158, IEC 61511 (automation and safety).

   

  🏗️ 5. Design

  5.1. Construction part

  The construction part includes preparation of the site, placement of foundations and buildings for the metering unit, auxiliary rooms (operator room, laboratory, power supply, cabling). The construction part is regulated by local construction norms and safety rules. Pro meter develops recommendations for the construction part, even if they are not directly provided for in the contract, since the metering station is impossible without proper construction solutions.

  Regulatory framework (construction part):

  • National construction norms and regulations.

  • Occupational safety requirements.

  • Environmental requirements.

  5.2. Technology and automation (selection of equipment)

  Technology is the main part of the metering station. It includes the selection of measuring instruments, provers, auxiliary systems and automation. At this stage the Customer’s requirements are studied, a list of required equipment is compiled, and Pro meter develops technological solutions together with suppliers and contractors.

  Pro meter prepares recommendations for:

  • Choice of flow meters (Coriolis, turbine, ultrasonic, differential pressure).

  • Choice of prover (pipe prover, compact prover, water draw system).

  • Laboratory equipment (densitometers, chromatographs, moisture analyzers).

  • Automation and SCADA systems, including interfaces with LIMS.

  • Protocols for communication: OPC UA, Modbus, Profibus.

  Regulatory framework (technology and automation):

  • API MPMS, OIML R117, MID (MI-005).

  • ISO 5167, ISO/IEC 17025.

  • GOST R 8.595, GOST 8.586.

  • IEC 61131, IEC 61158, IEC 61511.

  5.3. Sensors

  The sensor group is the “heart” of the metering system. Sensors are installed for flow, temperature, pressure and density. Their accuracy determines the overall accuracy of the metering system.

  Pro meter develops requirements for:

  • Flow sensors.

  • Temperature sensors (resistance thermometers, thermocouples).

  • Pressure sensors (absolute and differential).

  • Density sensors (vibrating densitometers, hydrometers).

  All sensors must have certificates of conformity and calibration protocols.

  Regulatory framework (sensors):

  • API MPMS.

  • ISO/IEC 17025.

  • GOST R 8.586.

    5.4. Power supply

    The main element of the metering station is the power supply system. Reliable power supply guarantees uninterrupted operation of the metering system. Pro meter prepares recommendations for:

    • Redundant power supply circuits.

    • Emergency switching systems.

    • UPS systems (uninterruptible power supply).

    • Requirements for grounding and lightning protection.

    Regulatory framework (power supply):

    • National power supply standards.

    • IEC 60364, IEC 61024.

    • Safety standards for hazardous facilities.

    5.5. Safety and ecology

    The safety system includes fire safety, explosion safety, industrial safety and environmental protection. Pro meter develops recommendations and requirements for:

    • Fire safety (automatic detection and fire extinguishing).

    • Explosion safety (compliance with ATEX and IECEx).

    • Industrial safety (emergency plans, instructions, staff training).

    • Environmental protection (protection of soil, water, atmosphere).

    Regulatory framework (safety and ecology):

    • IEC 61511 (functional safety of SIS).

    • National standards and regulations.

    • Environmental protection standards (ISO 14001).

    5.6. Documentation of the project: what must be available “at the facility”

    The final set of project documentation includes:

    • Terms of Reference (ToR).

    • P&ID diagrams with instrument tags.

    • FAT/SAT programs and acceptance protocols.

    • Calibration and verification methodologies.

    • Operating instructions.

    • Safety and environmental instructions.

    • Risk analysis and accident prevention.

    • Documentation of all measuring instruments with certificates and calibration protocols.

    • Documentation of automation and software (PLC/SCADA/LIMS).

    • Mapping of international and local standards (Standards Mapping Matrix).

    📌 All documentation is prepared in Russian, English and Latvian languages, if required by the Customer. Pro meter includes all documents in the Legal Shield package of the project, which guarantees their legal protection.

    📂 6. Project documentation: what must be “at the facility”

    Metering systems and metering stations are regularly inspected by commissions (state regulator, audit, arbitration). Therefore, the complete documentation package must be stored in safe access — in the administrative/control building of the station. The package provides a complete picture of the facility for the commission and ensures legal protection (Legal Shield).

    Mandatory set (paper + electronic archive):

    • ToR / technical requirements: plant project and supplier’s documentation.

    • Working technical project (P&ID, specifications, I/O, cabling logs, labeling).

    • Piping diagram of the metering system: certificates/protocols of primary verification and valid calibration/verification.

    • Instructions (operator, methods, calibration, maintenance), safety instructions, incident logs.

    • Test protocols (FAT/SAT, proving/calibration, verification), commissioning acts (pilot/industrial).

    Archive and access:
    Unified electronic archive with versioning, change log, time synchronization, notes in accordance with API MPMS, OIML R 117, GOST R 8.595, ISO/IEC 17025. Paper originals and electronic copies are available to the commission upon request and inspection.

    📌 Detailed composition in the template: see “Recommendations → Documentation” (2–4 pages A4: archive structure, checklists and forms for the commission).

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    🧪 7. Testing and primary verification

    Primary verification allows one to check the maximum operating modes and expanded grid of flow points/meters. Pro meter develops applied methodology for determining MX at all possible operating modes of the measurement system.

    The necessary set includes:

    • Institute of metrology (certificate and protocol).

    • Use of the metering station itself as a place for primary verification.

    This method is a mandatory addition to the Type Approval Certificate.

    Regulatory base: OIML R 117, API MPMS Ch.4/5/12, GOST R 8.595 and GOST 8.586.*, ISO/IEC 17025.

    🚀 8. Pilot-industrial operation (OPE) and final optimization

    The purpose of OPE is to determine the optimal operating modes of the system and modes of control of metrological characteristics. The accuracy of system operation, reliability, trustworthiness of accounting and accuracy of measurements depend on this.

    The result of OPE is the act of commissioning the metering unit into operation. The applied methodology of control is refined, the operating modes of the technological process are verified, and the parameters of regulation are clarified. Pro meter develops the applied methodology of calibration and verification of the system. Convenience for operation and technical maintenance of the metering unit is also ensured.

    For main pipelines, the typical duration of OPE is about 3 months, for commercial units it can be shorter.

    Regulatory framework: API MPMS (criteria of verification), OIML R 117, IEC 61511/61508 (functional safety), internal regulatory documents of the operator.

    🔄 9. Periodic verification, calibration and archives

    In operation, MX is confirmed in the same ranges, but with a smaller volume of measurements. A unified electronic archive of protocols/certificates is maintained, as well as acts of infrastructure verification (UPS, insulation, tightness), control sums of software, logs/protocols.

    All work is performed within the scope of technical maintenance.

    Regulatory framework: periodic verification schedules according to GOST/MI (by jurisdiction), OIML R 117, API MPMS Ch.4/5, ISO/IEC 17025 (documentation and data storage), requirements of the Customer/regulator for deadlines and formats.