Unlocking operational excellence
Published: 07 November, 2023
PWE takes a look at how developments in instrument condition monitoring can unlock operational excellence
Many industrial plants and processes rely heavily on a large range of process instrumentation. From water treatment plants to petro-chemical facilities, they all depend on flow meters, temperature and pressure transmitters and gas and liquid analysers to give accurate measurement and control.
Although the overwhelming focus of plant managers will be on the health and correct operation of the process, the instruments that provide the data also need attention. They must continue to operate reliably and accurately if the processes are to run as desired. This means that the health of the instruments themselves should be a major priority.
Smart devices measure own condition
Advances in technology have seen today’s process instrumentation become largely digitally based. These instruments produce a wealth of information about the process parameters they are designed to measure – they also use their digital features to report about their own performance and accuracy. Commonly known as condition monitoring, many modern devices can check their own circuits for errors and other issues, help technicians conduct calibration and evaluate their own performance.
Some of the benefits of device condition monitoring include keeping constant track of the health of measurement devices, often bringing the ability to share health check reports with the device vendor. Experts at the device supplier can then offer service recommendations based on the device’s health status and even offer remote assistance. Some providers take data from their devices and offer a full online condition monitoring system to enhance decision-making, putting information at users’ fingertips.
Reduced maintenance is another major benefit. Although many instruments are designed to minimize maintenance effort with self-cleaning and self-optimizing of active components, an accurate assessment of the condition of the device allows users to move to a predictive maintenance regime, avoiding the need to conduct scheduled maintenance that may not be necessary. This can be particularly useful if the device is in a remote area, is difficult to access or is part of a process that could pose risks to health and safety.
Another benefit is achieving maximum up time of the device. This is particularly important for critical operations such as gas emissions monitoring systems, which are becoming much stricter in many countries. For example, in the countries with the most restrictive regulations, operations may have only a maximum of 10 invalid minutes per half hour, a maximum of 5-6 invalid half hour averages per day, or a maximum of 10 invalid days per year.
Further options for condition monitoring of instruments include remote monitoring that can send condition alerts direct to a manager’s smartphone or tablet, keeping them constantly aware of how critical devices are performing.
Gaining all the benefits
The basic first requirement when seeking to taking advantage of these abilities is to get the right communications with the device. Most measurement devices are digital, though many applications continue to use the tried and tested 4-20mA current loop.
Some of the most advanced 4-20mA measurement devices also offer HART commun
ications, a bi-directional communication protocol that sends data to and from intelligent field instruments and host systems. An ability to interrogate the device is the next step and two common methods exist for interrogating device data. The first is inbuilt condition monitoring and diagnostics based on the NAMUR NE 107 standard. NAMUR NE 107 makes it easier for technicians and other process personnel who need to deal with alarms by categorizing internal diagnostics into four standard status signals — failure, function check, out of specification and maintenance required.
Each of these status signals can also contain greater detail. With a failure signal, for example, information could include whether the failure can be traced to the measuring device, or if the process itself is at fault.
With NAMUR NE 107 diagnostics, users have the option to turn off diagnostics that are not required – alternatively, they can configure how the diagnostics are reported.
ABB says all its measurement devices conform to NE 107, and it has used the standard alarm codes to build an online diagnostic app to offer the self-service support features that meet this need.
For example, if a flow meter is displaying an error code on the device’s HMI, users would simply choose the flow meter on the app then select the displayed error code from a drop-down menu. Entering the error code would return the nature of the fault together with suggestions to remedy the situation.
ABB also offers instruments that encrypt device maintenance and operating conditions within dynamic QR codes, making it easier for less experienced personnel to streamline troubleshooting processes, as they can simply take a picture of the QR code with their smartphone. They then forward the data securely to receive remote support.
Accurate verification in the field
One of the most important aspects of maintaining a device’s accuracy is field verification. Historically verification has been carried out manually, with engineers using multimeters and similar devices. Drawbacks typically include longer downtimes, and the need for specially trained technicians. A faster option is software verification, but this can involve using different software packages for different types of devices and one package may not work with all communications protocols.
The best modern verification software packages can be used for many device types, performing deep analysis of the device’s condition, with no need for any specially trained technicians. A report is produced on the calibration variables, assessing the limits and determining if the device has passed or failed.
Towards predictive maintenance
Condition monitoring is the essential basis of the most effective and economical type of maintenance - predictive maintenance.
Using performance data, predictive maintenance gives insights into which device and which component on the device is likely to fail and when. This allows maintenance staff to investigate the device’s condition more effectively. Maintenance tasks can then be conducted to comply with production schedules and conduct any repairs before the instrument fails.
A properly conducted predictive maintenance programme will dramatically reduce or even eliminate unplanned downtime caused by instrumentation failures. It can also help make more efficient use of the workforce, ensuring tasks can be scheduled more effectively. Another major benefit is the increased up time that can be gained - if an instrument is only taken out of service when absolutely necessary, it can continue to carry out its monitoring role for the maximum length of time.
Moving away from preventive maintenance and towards predictive maintenance can help eliminate routine tasks that add no value, reducing overall maintenance costs, while also eliminating the risk of making inaccurate adjustments. With a better insight into the actual condition of the instrument, it can be serviced in the way it requires, increasing its lifespan.
By aiding in their own condition monitoring to inform predictive maintenance, modern measuring and monitoring instruments are kept operational for longer. In this way, instrument users can ensure that their processes are also working for the longest possible time, cost-effectively and meeting all regulatory requirements.
Reap the benefits of digitalisation
With more industrial companies embracing digitalisation, the diagnostic functions included within digital instruments offer a raft of opportunities for enhanced operation and maintenance. Ultimately, whether a company moves towards more use of condition monitoring depends on several factors, including their current device setup, their operating philosophy, their perception of value and what they want from a potential supplier.
With the increasingly rich data sets now available from digital instruments, using digital diagnostics to improve accuracy, cut maintenance costs, boost quality and productivity and ensure greater compliance to regulations makes increasing sense.
For further information please visit: http://bit.ly/ABB_Digital_Servs.
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