Digitization viewed from a process analyser standpoint
Digitalization, digital transformation, industry 4.0, IIoT, etc. We’re constantly being bombarded with digital buzzwords. Industrial digitization or industrial process technology can often include robots, drones, big data, energy consumption, water management, safety, logistics, etc.
Less prominent are (chemical) inline or online process analysers. However, these analysers organise and control every production process. Whether it is a simple pH meter or an inline concentration or gas analyser, they ensure that the process runs optimally and sound the alarm if something threatens to go wrong. You might well say that process analysers are a crucial component in a process installation, which is precisely why it’s so strange that the digital possibilities of analysers are hardly ever used, if at all, and are certainly not fully utilized.
An analyser produces measurements
A sensor or an analyser is used to measure certain critical process parameters. The measurement results are then passed on to a higher level, a PLC, DCS or other process management system. Communication is often still analogue (classic 4-20mA signal and limit and alarm contacts). Nowadays this communication is increasingly digital via HART, (field) buses or Ethernet.
Whatever it may be, in most cases the information passed from the analyser is limited to the measured values, alarm and error messages. At the higher level, this data is processed further, combined with other information in algorithms, recorded and visualized. When considering digitalization and digital communication of analysers, this is often limited to the digital transmission of measured values and status information. In fact, a digital version of the old analogue functionality.
However, a modern analyser has more: especially more valuable information. This information is available digitally, but is rarely (optimally) used.
Analysers are quite complex in themselves and the analyses are not always obvious. Sensors sometimes have to withstand extreme process conditions and are subject to contamination and wear influenced by the process conditions themselves, which is precisely why analysers are regularly checked, verified, calibrated and possibly adjusted. Wouldn't it be interesting if information about the current status of the sensor, the latest calibration data and wear could be requested remotely? Consider how much time and cost can be saved with this. In fact, those possibilities exist!
Digital systems are not necessarily intelligent, but intelligent systems are always digital. This means that built-in intelligence is available digitally. Intelligent sensors can identify themselves with manufacturer, part number and serial number. They can indicate how long they have been in use, when they were last corrected (and possibly who did that) with the results. The degree of wear and / or the expected service life can be determined by self-learning (in accordance with process conditions) analyser-specific algorithms. In addition, the analyser itself sets the time interval until the next service.
This isn’t really news. These types of system have been around for a while. However, the information only remained local in the analyser itself. If you disconnect an intelligent sensor from the inverter (transmitter), all data remains stored in the sensor head. In the workshop or laboratory, the sensor can then be connected to a PC where all information is read. Calibration, verification, adjustment, etc. All of this can be done on your PC. Cleaning and maintenance are therefore done under ideal conditions. It goes without saying that errors and deviations are kept to a minimum. This of course enhances the accuracy and service life. And it saves you unnecessary costs. After maintenance and calibration, simply exchange the sensor on-site again. The firmware checks your sensor’s type and Tag number. This prevents the wrong sensor from being used by mistake. After all, the wrong sensor in the wrong place can yield inferior results and we want to avoid that. This contributes to process safety, product quality and process integrity.
Combine digital communication with intelligence
Above, we have been introduced to two aspects of digitalization of inline and online analysers. Firstly, the digital communication of measured values and status information to a higher level, secondly, the important analyser-specific information that is available digitally.
What happens if we combine both aspects? In that case, all available knowledge about the condition of the analyser, calibration data, wear and service life indicators and much more is available at process management level and accessible to everyone who has access to it, wherever the person is in the company. The sensor information becomes accessible via digital communication.
If we dare to think a little further and integrate intelligent sensors into the industry 4.0 concept, you can link the information about the service life of different sensors to inventory management. This ensures that at crucial moments, you never end up unexpectedly without the right sensor. At the same time, it is possible to easily determine the Cost of Ownership (CoO) of your analyser per measurement point (Tag), without additional administration of technical employees (who have better things to do).
Of course on-the-spot visual inspection of an analyser remains necessary! But this can now be done faster and easier using digital sensors. Using special tools you can read, comment on and save all information for further processing afterwards. Very useful if the digitalization has not yet been fully rolled out or if you need to maintain stand-alone installations in remote places.
It is quite interesting that the sensor does not have to be disconnected for this data recording. All signals remain active as usual, controllers are not disturbed and no (false) alarms are triggered. That way you no longer need a permit because the analyser does not go out of service. Speaking of time savings!
No display anymore
Electronic screens (computer screen, smartphone, tablet, displays, warning signs, LED screens, billboards, etc.) give us a view of the world. But sometimes it’s also possible without a screen. If you go through the digitalization of inline analysers, it appears that a screen or display is not necessary at all.
Calibration and maintenance is done remotely in the workshop. Measured values, status and alarm info are digitally visible in the control room and diagnostic parameters are available to the analyser specialists. On-site control connects to a PC, smartphone/tablet or handheld device. This can also be done for start-up and troubleshooting. Then why do you still need a local display? Just to look at the value when you pass? Actually, no.
Many inline analysers, ranging from simple pH meters through concentration analysers to laser spectrophotometers, no longer have a display. All measurements and information are digital. ProfiNet, ModBus, Ethernet ... it's all possible. Do you still work with a platform or protocol that is not compatible with your analyser? Not to worry, the advantage of digital signals is that you can convert them without loss of quality and without much effort.
In the industry 4.0 era, digital analysers and sensors are much more than just a gadget. The days when digital communication was a one-to-one replacement of the analogue signal are over. Digital analysers with intelligent sensors have so much more useful information in them. Information that can be requested by anyone who has the correct access rights and/or is linked to process management systems, whereby quality is improved and costs are reduced. In short: digital process analysers provide efficiency gains that are much greater than their cost.
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