Developments in Sensor Technology

25 February, 2015

First published in the February 2015 issue of Quarry Management as Sensory Perception

Tony Ingham, sales engineer with Sensor Technology Ltd, reports on cutting-edge sensor technology development and explains how sensors will define the future of production and technology

This past year it has been difficult to open an engineering magazine and not read about the Internet of Things (IoT), Industry 4.0 or Machine-to-Machine Communications (M2MC). But all the hype and predictions will come to nothing if sensor manufacturers do not rise to the challenges before them. The idea of Industry 4.0 first came to mass attention just a couple of years ago when it was a theme of the massive Hanover Fair in Germany. Experts and ‘futurologists’ will tell you that Industry 4.0 is different from the IoT and M2MC, but to those with a more down-to-earth understanding, they are effectively all the same – ways of significantly increasing the amount of data collected from production machinery and processing it in real time to produce better information, which, in turn, leads to increased productivity.

It is fairly obvious that the amount of data produced has been growing for many years and that this generally leads to better decision-making. However, there is such a thing as information overload, when people cannot pick the important information from a sea of data, so are unable to make appropriate decisions. But this is a human condition and it can be treated by using a computer to automatically categorize all the data by importance and displaying it appropriately (including emergency alarms, if necessary).

This real-time management of large quantities of data is a well-developed discipline and has become known as ‘big data’. This probably started in the control systems helping to run petrochemical refineries, spread to other data-intense applications and has evolved from there. It is now widely used in many diverse industries from oil and gas recovery to retail management, from weather forecasting to geological surveys, from agriculture to infection control, and from battlefield management to telecoms network operations.

Making data

So far this article has discussed using data, but in practice, it is necessary to produce the data before it can be used. This is where sensors come in and it is obvious that they are, in essence, the building blocks of Industry 4.0 etc. There are many types of sensor already in existence, from simple on/off switches and counters to much more sophisticated sensors, such as TorqSense, which continuously measures the torque generated by a rotating shaft.

It seems inevitable, therefore, that sensor technology is going to develop rapidly over the next few years. Sensors already exist to measure just about every useful parameter, including temperature, speed, production rate, colour, viscosity, weight, pressure and torque, so new types of sensor are not required. The forthcoming developments will take users in new directions.

One obvious requirement is for ‘intelligent sensors’, ie sensors with on-board (or at least local) data-processing capabilities. Instead of sending raw data to the central control system for processing, these sensors do some or all of the processing in the field. They thereby produce refined information, which may be in a number of different formats, each suitable for a different type of user.

Sensor Technology Ltd pioneered this sort of distributed intelligence some years ago and have a long history of supplying intelligent sensors for many diverse applications. Currently, not all users want this capability, but those that do reap considerable practical benefits and are essentially setting up their own bespoke Intranet of Things.

It is probable that the demand for intelligent sensors will grow exponentially with the take-up of the IoT and similar concepts. With the groundwork and fundamental developments already put in place by technology-led companies, the trend is free to develop unhindered.

Islands of control

A logical development of the intelligent sensor is the sensor LAN (local area network) or sensor cluster. In this, a number of sensors feed either raw data or processed information into a nearby controller for further processing. This produces a highly distributed control system architecture with attributes such as robustness, speed, agility and flexibility for change and development.

It is notable that a sensor LAN will be free to include different types of sensors, so could measure many diverse variables. It could also monitor, for example, the temperature in multiple separate locations and/or the torque in a number of different drive shafts. Therefore, the level of information it could produce and forward to different users could be very highly developed.

Other trends that can be expected in sensor development include cost reduction, miniaturization and standardization of communication protocols, plug-and-play, embedding capabilities, and signal quality enhancements. Sensors may also need to develop the ability to bypass the central control system and supply information straight to the Cloud or a remote data archive. Perhaps, above all, sensors will have to be hugely flexible, easy to install and remove, easy to connect into a control network, and easy to reconfigure for new duties.

Sensors used to be something of a Cinderella topic for control systems engineers – a bit of an after-thought and certainly not exciting. Now, however, they are rising to such importance that they could change the whole concept of control engineering.