We began exploring the key elements (5P’s) of Control System reliability and performance by looking at the considerations and recommendations around Protection with Cybersecurity. Here, we continue our examination of the 5P’s with:

Part II – Preventive Maintenance

Preventive Maintenance sets the foundation for the availability and peak performance of industrial control systems. Establishing processes and a regular cadence for experts to inspect, test, and maintain system components plays a crucial role in identifying and addressing potential issues before they degrade further into critical failures. Additionally, visits by experienced engineers help an organization lean on its unique expertise in identifying bottlenecks, optimizing performance, or simply recommending necessary adjustments and upgrades.

Preventive maintenance can be Utilization-based, Time-based, Predictive, or Diagnostic:

• Utilization-based maintenance – tracks actual usage of assets, environmental conditions, and operating parameters. Leveraging these data, future maintenance tasks are triggered to ensure timely intervention and optimal performance of the assets.
• Time-based maintenance – occurs at predetermined intervals in a calendar. Maintenance action may be triggered by said intervals or by plant-wide maintenance or turnaround schedules.
• Predictive maintenance – uses analytics applied to real-time sensor data, historical records, and operating parameters to trigger proactive maintenance actions. Predictive maintenance can help estimate the optimal time/margin before failure when maintenance tasks should be performed.
• Diagnostic maintenance – goes beyond predicting “when” failures might occur and focuses on understanding “why” they occur. This involves in-depth analysis and diagnostic procedures to identify possible root causes or underlying issues and come up with mitigation measures.

These strategies can help identify and address potential issues before they escalate to failures and downtime, ultimately maximizing and extending the lifespan of your control system assets. But no matter which one or combination of practices you employ, the following components are necessary to enhance the effectiveness of your maintenance strategy:

Elements of a Holistic Preventive Maintenance Program

1. Standardized Checklist Approach

Holistic maintenance leaves nothing to chance

Aside from ensuring that critical tasks are not overlooked, having a standardized approach to preventive maintenance establishes consistency across periods and across multiple sites. This involves creating a comprehensive checklist for maintenance inspections and activities. The  Preventive Maintenance Program Emerson developed for DeltaV distributed control system users includes an extensive roster of categories that service specialists review and check, including:

• System Updates and Hotfixes: Activities related to maintaining the overall integrity of the control system including review of relevant Knowledge Base Articles (KBA’s), Microsoft and antivirus system updates, hotfixes, and backups of the control system.
• Controllers: Activities include reviewing the hardware and software of the controllers, ensuring communications integrity, evaluating redundancy, and conducting basic health checks on the system
• Cabinets: Maintenance tasks related to conducting cabinet voltage analysis, assessment of power quality and general inspection of the hardware inside the cabinets.
• Workstations: Activities related to ensuring proper communication between workstations, maintaining overall integrity, conducting system cleanup, monitoring software and hardware, checking free disk space, implementing the needed hotfixes/KBA’s, and backing up alarms and events.
• I/O Subsystems: Inspection of LED indicators, checking overall integrity, verifying proper connection of IO carriers and cables.
• Network: Physical inspection of cabling connectors and assessment of cabling integrity of Smart Switches and Firewalls, ensuring they are undamaged and not subject to stress.
• Safety System: Checking communication status, monitoring LED indicators, ensuring smooth communication and verifying channel functionality.
• Backup and Recovery: Verifying whether the Backup and Recovery system is properly setup and functioning according to configured settings.
• Patch Management System: Ensuring that the installation is working properly –patches are downloaded, installed, and updated.
• Virtualization: Checking the proper function of virtualization components, including HW, clients and hosts.

There are many other aspects of a control system that are checked as part of a comprehensive preventive maintenance program; these may include: batch system health, database performance, OPC integrity, operator interface, or even ad hoc procedures which may be required by industry regulations or requested by the site maintenance team.

The benefits of having a vendor-guided or delivered preventive maintenance program include close alignment with the control system development, ensuring that the checklists also evolve as new technologies are developed and integrated into the DCS.

2. Automated Tools & Reports

People, Process and Tools combine for effective maintenance

The use of automated tools and collaboration technologies can greatly enhance a site’s preventive maintenance program. These not only ensure that no steps or elements are missed, but speed-up and streamline maintenance activities.

Some common maintenance tools and systems include:

• Condition Monitoring Systems and Diagnostic Tools –monitors the health of equipment and state of various parameters either real-time or on demand.
• Predictive Maintenance Software – employs machine learning and algorithms on historical data to predict failures and degradation.
• Computerized Maintenance Management Systems – platforms for managing and tracking maintenance activities which includes work orders, parts, and maintenance history.

In Emerson, results of preventive maintenance routines, including the standard report, are sent to an online collaboration portal accessible to both the customer and the local service team. This best practice ensures that both groups can visualize the results of the health checks conducted on the system and sees an updated action plan. Specific tasks are identified under this plan and assigned to either customer or vendor personnel which facilitates tracking to completion.

3. Certified Service Engineers

Reduce risk with certified engineers

A well-established certification process for service specialists ensures that vendor personnel coming to your site possess the necessary skillset and knowledge to handle your DCS and perform maintenance tasks effectively. This involves:

• Rigorous training and evaluation – typically covering all the major elements of a control system such as system architecture and components, troubleshooting, maintenance and update procedures and even regulatory compliance.
• Access to automated tools and deep knowledge base – certified service engineers are better equipped to identify potential issues which may affect your system, to correctly perform maintenance tasks, and adhere to industry standards and best practices.
• Continuous education and recertification – enforced by the factory – ensures that service engineers stay updated with the latest developments in the core system technologies as well as maintenance procedures.

Together, these elements of standardized processes, diagnostic and collaboration tools, and certification programs constitute effective and holistic preventive maintenance. Without them, control system reliability and performance objectives will be difficult to achieve and sustain.

Author’s Note:

While some solutions linked above are mainly for Emerson DeltaV control system users, the concepts and principles should generally apply to any other Industrial Control System. If you want to learn more:

• DeltaV Control System: Shaping the Future of Automation
• Operate safely, consistently and economically with Emerson’s Lifecycle Services

DeltaV Preventive Maintenance ensures the dependability and longevity of your system

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