Control System Assessments
Why do an Assessment In many cases the assessment is performed for strategic reasons. While it does not solve any problems or make any improvements, it does provide valuable information about the control systems within a facility or enterprise. The assessment can provide a blue print for future activity including capital budgeting, work-force development, hiring, risk analysis, spare parts inventorying, maintenance planning, standardization planning, etc. A good independent study can be time-consuming if performed with internal resources or can be of significant costs if performed with outside resources. So, make sure there a value to your organization. How is an Assessment Completed A list of individual control systems should be tallied. The main heading of the list is more than likely going to be machine name or process step. What should be included in an Assessment All the significant components in the control system are listed. These components should include the PLC/Main Controller, HMIs, Motion Controls, Robots, Safety Controllers, Temperature Controllers, and complex sensing devices that require software configuration like vision systems, safety scanners, process transmitters. (There is not much value in listing items such as power supplies, relays, operator controls, and basic sensing devices.) Then the attributes about each component are collected. These include manufacturer, model number, vintage and firmware revision. We also want to know about the tools required to modify or recover the components. Are these tools readily available? Are there personnel that know how to use them? Is there back-up files or documentation that is valuable to recover from complete component failure. Are new or re-conditioned spares readily available? These items are best organized using a spreadsheet program. And finally, the component should receive a calculated overall score based on the collection of attributes. The Final Report The most important part of the report is a listing of the components that received a poor score. It should indicate the reason(s) for the score and recommended action plan to remove it from the list. Then there are a range of summaries that can be drawn from the collected data. For example, a summary of the variety of installed PLCs per the manufacturer. Or if the PLCs are all from one manufacturer, a summary per the platform type or firmware revision. There might be a summary of which components are supported by a Windows 7 programming/configuration software. And on, and on, and on…………