Plant & Works Engineering
Finding the missing link
Published:  07 August, 2014

Computerised Maintenance Management Systems (CMMS) are now widely used throughout industry and especially in the process sector. Their adoption demonstrates a great advance over the old daily, weekly, monthly routines, which used to form the basis of a plant maintenance strategy. PWE reports.

Today a CMMS software package maintains a reliable and efficient database of an organisation’s maintenance operations and this information is used to schedule maintenance workloads and help management to make informed decisions on the functional status and safety of plant equipment and facilities. However, many CMMS do not have the capability to handle the data relating to the calibration of process instrumentation. New software and hardware is now available to fill this important gap.

Calibration within a maintenance regime

Calibration of process instrumentation is a necessary function both to comply with regulation and to maintain and control process performance and product quality.

Regulation is vital to ensure plant and process safety and calibration is now mandatory throughout the process industry. Regulation is also especially important where traceability is vital to ensure the quality of sensitive products. Calibration for process and product quality control is something that improves the bottom line. Product quality must be maintained and monitored to eliminate any wastage issues or customer litigation. Process performance must be monitored to ensure efficiency of operation as well as plant safety.

Calibration needs to be carried out because all measuring devices drift over time and calibration ensures we are measuring to the accuracy required, accuracy set on installation or accuracy set later to some agreed value.

Having established the need to calibrate, it is then important to decide when to calibrate. Sometimes calibration strictly follows manufacturers’ recommendations. Some organisations prefer to calibrate on a regular frequency basis, such as annual shutdown. Historically, such calibration sometimes involved taking the measuring device out of service and sending it to a calibration lab. However, neither of these regimes is a perfect solution because, as already mentioned, instruments can drift between calibration intervals. An obvious answer to this is to calibrate more frequently, but this entails increased time and cost, both in lost production and in calibration resource. Fortunately, with the introduction of the latest generation of smart, portable calibration instruments, integrating with today’s sophisticated calibration and maintenance management software, it is possible to automate the calibration process and often possible to increase calibration intervals while still maintaining the required compliance with regulation and meeting standards relating to process and product quality and safety.

Collecting and managing calibration data

Today’s advanced portable calibrators can store a vast amount of data and can even be used to create and review calibration certificates and custom reports, which can be electronically signed off. Built-in calibration management software is available to automate the calibration by executing pre-programmed routines which determine the correct setup for the device, the calibration sequence and analysis of the results including the pass or fail status. This can allow impressive time savings. This same calibration management software can also schedule work and even analyse instrument trends. And the latest instruments, such as the Genii from the Druck product line of GE, also acts as a communicator, so that it can be used to configure and commission HART-and Fieldbus-enabled devices.

Mike Shelton of GE Measurement & Control explains that a really important feature of the Genii instrument is its ability to interface with calibration and maintenance management software, such as GE’s 4Sight, which provides a web-based solution. This hardware/software package offers mobile, paperless calibration and maintenance management and can help companies meet regulatory compliance by providing continuous availability of records and data for audit to recognized quality systems. It also features a number of tools for resource management and efficiency improvement. These include a tool for Interval Analysis, which enables users to report quickly on device performance by scientifically analysing historical data and drift to allow informed and qualified calibration interval recommendations (which may be longer than manufacturers’ recommendations). There are also tools for performance management, providing Key Performance Indicators (KPIs) in real time and a deviation management tool, which ensures that calibration failure notifications are sent in a timely and controlled manner and avoids operators having to manually review every calibration.

Shelton adds that 4Sight can interface seamlessly not only with Genii but also with existing high-end Computerised Maintenance Management Systems. This enables the automatic download of procedures and the direct upload of results, ensuring paperless calibration and maintenance, with total integrity of data and no chance of transcription errors. Scheduling can be automated and worksheets sent directly, in a logical fashion, to the appropriate operators and calibration activities, and data, can become an integral part of a CMMS.

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