The smart way to measure
Intelligent sensor management systems for greater productivity in process analytics

Experts estimate that measuring point failures account for up to one-third of the cost of unscheduled plant downtimes. Furthermore, the operating costs of a measuring point can amount to four times the procurement cost. What’s required therefore is useful, wide-ranging and above all reliable predictive information about ongoing operations.

lever sensors store information, but intelligent sensor management systems go one step further: they use information adaptively. These new instruments focus less on detection technology and much more on communication, query and performance status options. This has developed not least due to the fact that process analytics suppliers have become increasingly orientated towards their customers’ requirements for more information, improved reliability and reductions in maintenance costs.

This was how Mettler-Toledo came to develop its new intelligent sensor management concept — or ISM for short — for the measurement of pH, oxygen, conductivity and turbidity. With this system, sensors are only replaced when recommended by the "Wear sensor monitor". An ageing electrode can also be changed before a critical process incident occurs. "As well as sensor performance, the big difference compared to previous designs is this new second dimension — intelligence. In other words, you can now go right down to the deepest sensor levels which are then actually measured in real time as well. Therefore, the predictive information is not computed but current and specific. That’s why we expect this predictive probability system to go far beyond what has been available up until now," claims Thomas Nitschke, Head of the Process Analytics Division for Central Europe at Mettler Toledo. Process reliability is thus significantly increased.

Simple yet intelligent

Process and maintenance operators will be the main beneficiaries of ISM. Automatic transmitter configuration for the sensor settings, fast fault diagnostics and ongoing recording of diagnostic data remove a great deal of dedicated staff capacity from the system. "Fewer downtimes are also an obvious difference with Intelligent Sensor Management Systems," explains Nitschke. Plant availability is also increased with the faster startup, a host of fault diagnosis options, an adaptive sensor diagnostics system and fast installation with "plug and measure" functionality. And this system also represents a real asset for operating and technical engineers. Operating errors on the transmitter are kept to a minimum, mainly because all the relevant sensor status and configuration data is transferred automatically when connected to the transmitter. Sensors are identified immediately and the data saved in the transmitter. What‘s more, all the pH electrodes and oxygen sensors can be precalibrated in the laboratory, eliminating the need for calibration directly at the measuring point. The specific ISM measuring points identify the manufacturer, type of sensor, serial number, item number and date of last calibration. Previous data records are also available to carry out trend analyses.

Digital data transmission

A specialty available to Mettler-Toledo customers is that of digital signal transmission. The company first demonstrated this function for users in April at two events in Würzburg and Bottrop (Germany). Above all, a digital system means one thing: the uninterruptible and reliable transfer of data. Receiving predictive diagnostics information in this way allows for better planning for sensor replacement. This is because all measuring data is continuously monitored in order to obtain long-ranging information on sensor wear. Adaptive calibration timers also monitor process conditions and regulate calibration intervals autonomously for critical process conditions. "It’s not least why we have so much success with this sophisticated system particularly with customers who want or need to calibrate and clean automatically. There are considerable cost savings to be made as a result of the reduced staff requirement," continues Nitschke. Finally, ISM systems also support operating engineers and supervisors, as maintenance teams are able to carry out "out-of-the-box" installation of factory-calibrated sensors. Further calibrations can then be carried out in controlled laboratory conditions and downloaded automatically on site. But in the final analysis it’s not just the technical parameters or design which ultimately decides whether a concept really works to the optimum extent — not even with the ISM concept.

Service is a firm fixture

Without the support of experts right from the start, the user will not be able to reap all the benefits straight away. "A well-organized Service Department is at least as important," declares Nitschke from his own experience. "There’s clearly a service requirement among manufacturing SMEs in particular, as the capability is rarely present or because it’s simply not considered to be a need." And so this task is often outsourced and a relevant partner is then required. That’s why sensor suppliers looking to the long term have now ceased to regard service as a cost factor only but rather as a coefficient in their customer retention strategy and hence are now extremely successful. n