Integrating Third-Party Systems with a Distributed Control System (DCS): Checklist

Integrating a third-party system, such as a programmable logic controller (PLC), with a Distributed Control System (DCS) is a critical task that involves multiple considerations to ensure seamless communication, data integrity, and system reliability. 

This integration can be achieved through different approaches, each with its own advantages and potential challenges. The choice between using a Supervisory Control and Data Acquisition (SCADA) interface or a peer-control solution depends on the nature of the data being integrated, the required response times, and the overall system architecture.

What is a Third-Party System in the Control System? 

A third-party system in a control environment refers to any external unit, equipment, or electronic device that generates process or operational data. Unlike conventional input/output (I/O) devices, these systems require specialized communication protocols to interface with the DCS. 

Some examples of third party systems are power generation units, multiphase flow meters, MPFM, and gas compressors in an oil and gas processing plant. These systems are normally stand alone systems with their own control systems like PLCs but they require to pass some important data to the DCS system. The integration of these systems requires the application of hardware, software and communication interfaces that are not typical of I/O.

Third-party systems are connected to a control environment through gateways or protocol converters such as Modbus or Ethernet/IP. It maintains data consistency for the processes’ accuracy; however, there are issues with compatibility because of the proprietary standards. These systems provide the features such as scalability, flexibility, redundancy, and superior data analysis. Security, following the industry norms, and vendor assistance are vital. Training of personnel is crucial in the running and maintenance of the facilities. Therefore, third-party systems improve control systems by incorporating new technologies without disrupting the existing framework, which guarantees dependable, effective, and secure operations.

Interfacing Protocols for Third-Party Integration

There are two primary methods for integrating third-party systems with a Distributed Control System (DCS):

1. SCADA Interface – DCS Server as the Middleman
2. Direct Interface with DCS Controller (Peer-Control Approach)

Method 1. SCADA Interface – DCS Server as the Middleman

In this method , the DCS acts as a SCADA system, with a server within the DCS environment functioning as the intermediary between the third-party system and the DCS controllers. This method involves setting up a SCADA database within the DCS, typically showing  the third-party system’s data points.

Configuration

SCADA points are configured using tools specific to the DCS, such as Honeywell’s Quick Builder. This tool helps create and maintain the configuration database, including channels, controllers, and points.

Advantages

The operator benefits from a unified interface, using the same faceplates, trends, and displays for both DCS and third-party data. This approach is ideal for stand-alone systems with minimal interaction with the DCS.

Challenges

The DCS server becomes a single point of failure, particularly if data needs to be passed to DCS controllers. This can introduce delays and potential vulnerabilities in case of network issues.

Example

A power generation unit using Honeywell’s Quick Builder to set up SCADA points that mirror the data points from the generation unit.

The operator can monitor and control the power generation unit through the same interface used for other DCS operations.

If the DCS server fails, data from the power generation unit may not be accessible, impacting overall system performance.

Method 2. Direct Interface with DCS Controller (Peer-Control Approach)

In the peer-control approach, the third-party system communicates directly with the DCS controller, bypassing the need for a SCADA server. The DCS controller is equipped with appropriate drivers and communication protocols to interface with the external system.

Configuration

Examples include using Yokogawa’s ALE Card Model ALE111 for Ethernet communication or DeltaV’s Serial Card for direct interfacing.

Advantages

This method is suitable for integrating systems that require direct, real-time interaction with DCS points, such as safety instrumented systems (SIS) that manage critical process trips and permissives.

Challenges

Care must be taken not to overload the DCS controller with communication tasks, which could impact its primary processing duties. In some cases, a dedicated communication controller may be required to handle the data flow.

Example

A multiphase flow meter (MPFM) using Yokogawa’s ALE Card Model ALE111 for direct Ethernet communication with the DCS controller.

Real-time data from the MPFM is directly available to the DCS for immediate process adjustments and safety measures.

Ensuring the DCS controller isn’t overloaded with communication tasks, which might require a dedicated communication controller to manage the data flow effectively.

Based on your system needs and operational priorities, you can choose the best integration solution by being aware of these techniques and their unique benefits and drawbacks.

Checklist for Integrating Third-Party Systems with a DCS

It is essential to stick to a thorough checklist when integrating third-party systems with a DCS in order to minimize potential risks and ensure effective deployment. This checklist guarantees that all technical issues are covered. An extended checklist to help with the integration process is provided below:

Step 1. System Requirements Analysis

• Define the third-party system you are integrating with the DCS, such as MPFM, compressors, or power generation units. Understand its specific role and function within the control environment.
• Clarify the goals of integration, such as centralized monitoring for unified oversight, data aggregation for enhanced analysis and reporting, or real-time control to influence and monitor the third-party system.
• Identify all critical data points and parameters from the third-party system that need to be integrated with the DCS. Examples include mass flow rate and density for MPFM, or bearing temperature and engine lube oil pressure for compressors. Ensure you understand the type of data (analog, digital, alarms) and accuracy requirements.
• Decide the direction of data flow between the third-party system and the DCS whether unidirectional (from third-party to DCS) or bidirectional (allowing communication in both directions). Establish data update frequency and how the DCS will handle and process this data.

Step 2. Selection of Interfacing Protocol

• Choose a suitable protocol for integration, such as Modbus, Ethernet/IP, or Profibus, considering factors like system compatibility, data rate, and reliability requirements.
• Verify that the existing network infrastructure supports the selected protocol and can accommodate the additional data load without performance issues or degradation.
• Decide whether to use a SCADA interface (where the DCS server acts as an intermediary) or a direct DCS controller interface based on factors like data criticality and the level of interaction required.

Click here for knowing about Network Switches requirements in “SCADA” and “DCS” Architecture

Step 3. Hardware Configuration

• Choose the appropriate communication hardware, such as Ethernet modules or serial communication cards, for both the DCS and the third-party system to facilitate data exchange.
• Verify that the selected communication modules are compatible with both the existing DCS hardware and the requirements of the third-party system to ensure seamless integration.
• Implement redundant hardware paths where necessary to prevent single points of failure, especially in critical applications, to enhance system reliability and uptime.

Step 4. Software Configuration

• For a SCADA interface, configure the SCADA database to include data points, alarms, and historical data from the third-party system. Ensure that all relevant data is accurately represented and accessible.
• For direct interfacing, configure the DCS controller to handle third-party data by setting up the necessary logic and communication parameters. Ensure the controller is programmed to process and respond to data from the third-party system effectively.
• Install and configure the required drivers on the DCS server or controller to enable communication with the third-party system. Ensure that the drivers are compatible and properly set up to support seamless data exchange.

Step 5. Communication Setup and Testing

• Establish and set up network settings, such as IP addresses, subnet masks, and routing, to guarantee that the DCS and external systems communicate with each other. Check to make sure devices can be reached and that the network settings are correct.
• To ensure that the DCS can send and receive data from the third-party system successfully, run preliminary testing. Look for problems with connectivity and confirm that data exchange is operating as it should.
• Create error-handling protocols inside the DCS to handle faulty data or poor communication. Establish alerts or alarms to inform operators about issues and, if required, set up retry procedures.
• Monitor throughput and communication latency to make sure they fulfill the performance needs of the application. Check that reaction times and data transfer rates fall within reasonable bounds for effective functioning.

Step 6. Integration Testing

• Verify that the integrated system performs as expected by ensuring all data points from the third-party system are accurately transmitted and displayed in the DCS.
• Simulate both normal and peak operational loads to assess system performance. Identify potential bottlenecks or overload issues to ensure the system can handle expected traffic.
• Confirm that alarms, events, and status signals from the third-party system are correctly processed by the DCS. Check that they trigger appropriate responses and are displayed accurately.
• If redundancy measures are in place, test the failover mechanisms to ensure the system maintains continuous operation during hardware or network failures. Validate that backup systems activate seamlessly and without interruption.

Step 7. Documentation

• Keep thorough records of the whole integration process, including information on program setups, hardware configurations, network settings, and test outcomes. This documentation should to be used as a guide for maintenance and troubleshooting in the future.
• Ensure that all important configuration files, SCADA databases, and DCS logic programs are kept in backups. This guarantees that configurations can be promptly cloned or restored in case they are required.
• Provide training materials and user manuals for maintenance crews and operators. Provide thorough operating instructions for the integrated system along with troubleshooting steps to help with any potential problems.

Step 8. Training for O&M Team and Handover

• Conduct comprehensive training sessions for operators to ensure they are proficient in monitoring and controlling the third-party system through the DCS interface. Cover key functionalities, data interpretation, and routine operational procedures.
• Provide detailed training for maintenance personnel on troubleshooting communication issues, addressing hardware failures, and performing system diagnostics. Ensure they are familiar with the new system’s components and maintenance requirements.
• Complete the integration process with a formal handover to all relevant stakeholders. Verify that everyone involved is satisfied with the system setup and understands how to operate and maintain the integrated system effectively.

Step 9. Post-Integration Monitoring and Support

• Establish continuous monitoring to keep checks on the integrated system’s reliability and efficiency. Utilize diagnostic tools and notifications to quickly identify and resolve any problems.
• Provide a thorough support plan that covers updates, troubleshooting techniques, and regular maintenance schedules for the third-party system and the DCS. Make sure that resources for assistance are easily accessible.
• Make any necessary configuration adjustments and do routine performance evaluations of the system. To sustain optimal performance and integration efficiency, adjust to shifts in operational requirements or technology breakthroughs.

Comprehensive Checklist for Integrating Third-Party Systems with a Distributed Control System (DCS) – Downloadable

This checklist offers a step-by-step guide to streamline the integration process, covering all critical aspects from initial analysis to post-integration support.

Download the comprehensive checklist to ensure a smooth and effective integration of third-party systems with your DCS with below link

What is DCS integration?

Incorporating a Distributed Control System into industrial operations is known as DCS integration. It includes setting up networks, implementing software, connecting hardware, and coordinating with current processes. Field equipment, control algorithms, communication protocols, and user interfaces are all integrated in the process. 

By centralizing monitoring and control, it seeks to increase reliability as well as effectiveness. DCS integration streamlines operations and improves overall plant performance, which is critical in sectors like chemicals, power generation, and oil and gas.

How do you integrate PLC and DCS?

Establishing a seamless communication network between these two control platforms is a necessary step in integrating PLC and DCS systems. This is usually accomplished by establishing shared variables and data points, utilizing hardware interfaces like gateways or interface modules, and implementing common protocols like Modbus or OPC UA. 

Establishing industrial Ethernet or fieldbus networks, installing DCS software to read and write PLC data, and making sure that all systems are in sync with one another’s time are all part of the process. 

Important actions include establishing standardized operator interfaces, putting cybersecurity protocols into place, and coordinating alarm management. This connection facilitates smooth information flow between plant-level control and higher-level management systems, improving overall system functionality, data accessibility, and operational efficiency.

Click here for to download DCS Alarm Management Checklist

What is a third-party system in a control environment? 

A third-party system refers to any external unit or device that generates process or operational data, such as power generation units, multiphase flow meters, or gas compressors.

Why is integrating third-party systems with a DCS important? 

Integration ensures seamless communication, data integrity, and system reliability, allowing for centralized monitoring and control of diverse systems.

What protocols are commonly used for third-party system integration? 

Common protocols include Modbus, Ethernet/IP, and Profibus, chosen based on system compatibility and data requirements.

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