Cleanzone 2017: Digital monitoring solutions facilitate efficient controls, traceability and fault detection

© vali.sys

Has the permissible particle concentration been exceeded? Is the relative humidity over the limit? Is an excessively high temperature endangering the stability of an active ingredient? In these cases, or any other time that critical conditions arise in cleanrooms, personnel can benefit from proper digital monitoring, as it makes it possible to trigger immediate alarms, obtain a comprehensive overview of the situation, react rapidly and take prompt countermeasures. Even so, it is not always easy to integrate modern processes into the analogue structures that have developed over the years at a pharmaceutical company. Seeing as cleanrooms are particularly sensitive areas in every respect, they are also in a position to be among the pioneers in the field of digital monitoring. A visit to this year’s Cleanzone trade fair on Tuesday and Wednesday, 17-18 October 2017, in Frankfurt am Main, offers a glimpse of what the future holds.

In many areas of pharmaceuticals production and analysis, the advantages of comprehensively networking machines, measurement equipment and documentation systems are evident. In keeping with “Industry 4.0”, modern digital solutions facilitate efficient controls, the traceability of lots and the detection of possible irregularities or faults. Yet not everything that delivers digital values is actually digital from start to finish. There are also ‘semi-digital’ systems, as well as physical conditions that can make it necessary to establish an interface between analogue and digital systems.

A good example is offered by the monitoring of sterile production, filling and/or packaging for pharmaceuticals, in which case the data generated is generally analogue. The key parameter is the number of airborne particles in a predefined volume of air. In industrial practice, this parameter is measured under GMP (Good Manufacturing Practice) conditions in cleanroom zones A and B continuously, while values for zone C are recorded on anything from an hourly to monthly basis, and for zone D anywhere from daily to yearly. Due to the fact that particles can be seen as potential carriers of biological contamination, the data provided by the particle counters is also fed into the risk assessment for biological contamination.

Furthermore, other factors such as the differential pressure between various cleanroom zones, and naturally also between the cleanroom and impure areas surrounding it, are also monitored continuously. The relative humidity is often another important parameter. As a general rule, it is also recommended that the temperature be monitored for any location in which medications or other products remain for more than 24 hours. Regardless of whether they are determined via a resistance measurement or by other means, the data produced are primarily analogue.

Directly after measurement: analogue is converted into digital

In traditional plants, the data are largely transmitted via analogue cables. However, the digital alternative offers significant advantages: whereas an analogue cable can only ever transmit one signal, a digital cable is able to transmit a great deal – after all, that is why it is possible to receive so many television channels today, rather than just two or three. In the field of measurement technology, this principle also makes it possible to collect large volumes of data from multiple locations and communicate it outside the cleanroom by means of a single cable (e.g. Modbus systems). At the same time, it is possible to check that the equipment is functioning properly, in order that any ‘faltering’ sensors can be quickly recognised and replaced, for example.

Digital transmission is also helpful when it comes to determining the reliability of the results. Just as the picture would often become distorted on the televisions of old, analogue signals in general can be disrupted by motors, other drive systems or screens. With digital transmission, on the other hand, you either receive an excellent image / clear signal, or nothing at all (= system fault).

If the data is always collected in analogue form, and data storage, including the presentation of data over time etc., is always performed in digital form, it is only natural to ask: at which point should the signal be converted? In order to minimise the possibility of disruption, it is best to convert the signal as close as possible to its source. With modern sensors it is possible to complete the entire process within two millimetres of the sensor itself – both the purely technical analogue-to-digital transformation and the conversion into the desired measurement value while accounting for the calibration data.

Will everything be wireless in future?

If we take “Industry 4.0” seriously, it should be possible to do more than simply generate the digital value directly at the sensor. We should also be able to correlate values from various sensors and even involving different parameters (particle load, temperature, relative humidity) with one another. To this end, multiple devices in the cleanroom would communicate with one another, so that warning signals could be sent to the control centre even before individual threshold values are exceeded: “Warning: while everything is still okay, the measurement values are moving towards a situation in which normal operating conditions could be breached.” Is this a realistic hope?

“It is already possible for control systems to independently switch off machines when the particle concentration exceeds permissible levels. The control centre is then informed of this afterwards,” explains Thomas Christen, Technical Director at vali.sys in Wetzikon, Switzerland. “Naturally it is also possible to conceive of a pool of various measurement data rather than just a single target-actual comparison. While this is rarely seen in actual practice, it is a method that holds promise for the future.”

Among the concepts put forward are systems with sensors that transmit data wirelessly to the cloud, from where any relevant alarms are triggered. For users, this means no server, no updates and access from anywhere – an entirely internet-based system. “Food producers and climate-controlled warehouses are already taking advantage of the opportunities this offers,” reports Philippe Trösch, Sales Engineer for Novasina in Lachen, Switzerland. “For companies that are hesitant to take action here, be it for regulatory reasons or due to other concerns, or who do not wish to do without their existing server structure, for example, the solution is clear: extremely modular systems.” Their utilisation in cleanrooms as separate, moderately-sized ‘self-contained worlds’ might even be particularly suitable here.

Visitors to Cleanzone will be able to transport these and other ideas to their own operations, and may even be able to begin putting them into practice the very next day – whether within the framework of advantageous concepts for a new installation or as part of a gradual integration of digital monitoring solutions into existing pharmaceutical cleanrooms.