Radar level meter with IO link for lightning-fast measurements

The first non-contact radar level meter for really fast work

Non-contact radar level measurement has now become a very robust and accurate measurement method in the industry. For applications in which extremely high measurement speeds are required, such as in a filling carousel in a soft drink factory, until recently capacitive measurement was often used. With the introduction of the VEGAPULS 42, a non-contact radar level meter with IO-link connection, this robust measurement can now also be used in these types of applications.

In factory automation, IO-link is a protocol that is increasingly being used. The protocol has added value over other protocols in certain applications in industry. Especially when smart instruments are used, IO-link offers advantages over existing protocols. Looking at measuring equipment, an IO-link connection allows, for example, a sensor to be swapped for another sensor without having to reset the new sensor. That can also be a completely different type of sensor. Rob Smulders, Business Development Manager at VEGA, explains, "Suppose you have a conveyor belt on which you have an ultrasonic measurement or a laser measurement. That meter no longer works and you replace it with a radar level meter from us. Because a number of sets of specific parameters are defined in the IO-link protocol, you can change that sensor and continue your production immediately."

Factory automation vs process automation

In factory automation, IO-link is a protocol that is increasingly being used. The reason the process industry is less interested in it is due to the fact that the maximum cable length from a sensor to the IO Master is only twenty meters. In a refinery, which spans many square kilometers, that is not an option. In those cases, the two-wire analog 4-20 mA signal is commonly used. The HART protocol also uses that signal, with the addition of a superimposed signal with which to send data. Smulders: "That is a very stable connection, but it is enormously slow."

IO-link is a digital protocol that provides very fast data transfer and uses a three-wire connection.

Two wire and three wire

For process automation, a new way of transferring data that allows users to work with cable lengths longer than twenty meters is being worked hard on. This technique, Advanced Physical Layer (APL) was written about, for example, in Process Control no. 7 of 2022. "By definition, however, APL uses a two-wire network," Smulders clarified. "While high speeds can be achieved with this, two-wire links are limited in power. For that reason, two-wire connections can be used in ATEX environments. Three-wire connections are unlimited in power, but cannot be deployed in ATEX environments."

More power is more speed

The fact that three-wire connections have unlimited power has a big advantage for instrument makers. Smulders: "Having unlimited power allows us to send much more power to the sensor, which means we can make much faster sensors." And that is exactly what makes the VEGAPULS 42 so special. This radar level meter has a refresh rate of 18 Herz, whereas a "normal" radar level meter has a refresh rate of 4 to 5 Herz. "So that approach yields a sensor that, although you can't use it under ATEX conditions, it measures incredibly fast."

Capacitive

The area of application of the VEGAPULS 42 therefore lies in situations where many measurements per time unit must take place. One should think especially of factory automation applications, for example in food. Smulders: "Think of a soft drink factory where you have a filling carousel in which several small tanks are used to fill bottles and vials. That process goes at an enormous speed and the levels in those tanks go up and down correspondingly fast. Until now, capacitive measurements have been used for that kind of application. While these are fast enough, they have the disadvantage that you have a rod in your tank that makes cleaning difficult. The coatings of these measuring rods can degrade over time, requiring you to replace them. Also, when measuring with only one rod in your medium, you have a shadow on the other side of your medium. In short, non-contact radar level measurement is simply much more practical than capacitive measurement."

More than just hygienic benefits

The VEGAPULS 42 is an ideal solution for the above application in the soft drink factory, Smulders knows. "The measurement takes place contactless, can effortlessly achieve the required measurement speeds that are demanded in this type of process and our radar level measurement has now proven itself in practice for years as a very robust measurement." The advantage of such measurement over capacitive measurement, by the way, is not limited to hygienic benefits. "You can also save on energy consumption," Smulders knows. "If you only have a min-max measurement, as with a capacitive measurement, you can indeed switch your pump on and off, but the moment you want to optimize the energy consumption of your pump, you need more than just the lower and upper limits."

With the VEGAPULS 42, the speed at which the holding tanks in the process are emptied and filled becomes clear. "When you have a clear picture of that speed, you can determine at what percent of power your pump should be running to keep the process running continuously, without having to constantly start and stop the pump. Because you no longer have to start and stop every time, you save energy. With just a min and max measurement, you don't have enough data to realize those energy savings."

Compact footprint

The VEGAPULS 42 has a range of fifteen meters and can therefore be used on larger tanks. But, Smulders believes, the sensor will be used in the future mainly in high-speed installations with small tanks. "In many other applications, you can make excellent use of our other sensors, but if you want real speed, you need power and that's when you end up with the VEGAPULS 42." Also nice is that the VEGAPULS 42 has an extremely compact footprint. "With such a filling carousel in food, you really don't want to install sensors as big as a shoebox. That just doesn't fit. Our new level gauge you can really install above any tank or filling bunker because it's so small. Because we wanted to keep the footprint small, we chose a compact antenna. That means you can't deploy the sensor in silos that are deeper than 15 meters." In addition, a radar level meter is not affected at all by agitators in the silos or drums, something that is common in food.

Connections

The VEGAPULS 42 comes with various connection options. It is supplied from ¾ inch, for hygienic applications from 1 inch. Yet each user often has his own connection, Smulders also knows. "You have triclamp, milk couplings and so on. Fortunately, we have developed an adapter system with which every VEGA sensor can be converted to the required process connection, also hygienically." 

The technology in the VEGAPULS 42 comes from VEGA's PRO series. The sensor thus contains the proven 6X chip, which is produced in-house by VEGA (see also the box). "That chip is actually a further development of our previous chips, which were also already incredibly good." A feature of the 6X chip is the 80 GHz radar with a high dynamic range, which allows excellent measurement of many different media. 

App

Like the other level meters from VEGA, the VEGAPULS 42 is also equipped with an app with which the sensor can be adjusted. Smulders: "I often jokingly tell customers that even my mother can use such a sensor, but it really is. It's just super easy. If you give me five minutes, within that time I have a sensor set up and you can get on with your process. The app really makes it a lot more attractive for the customer to get started with our product. There are staff shortages everywhere, and TDs no longer have the time at all to spend a day studying a new sensor."

Foaming

Prices of the VEGAPULS 42 start at 1,100 euros in stainless steel version. With the same chip, both solids and liquids can be measured. Smulders: "Where previously with other sensors you really had to worry about the medium in which you wanted to measure, this is now no longer an issue at all. Foaming is also less and less of a problem. I do note that foam comes in all shapes and forms. From the foam on a fermenter to the kind you find on your beer in your glass. The latter type no longer poses a problem at all. We easily measure through that."

Also 4-20 mA

Although the VEGAPULS 42 can be connected as an IO-link instrument, it can also be connected with 4-20 mA. "For some parties it is a nice idea that they can get started with 4-20 mA now and in the future, if they decide to work with IO-link, be able to use the same sensor using the IO protocol," Smulders clarifies. Whether IO-link will become the protocol for the future, no one can say. "The fact is that the major instrument manufacturers are now betting quite heavily on IO-link for factory automation. So I certainly don't see this protocol disappearing just like that."

The VEGAPULS 6X 

VEGA released a new radar level meter for process automation in 2021 that makes level measurement even simpler. The VEGAPULS 6X is a level meter that can be used for all applications. Where previously a sensor was selected according to specific process characteristics such as medium, temperature and process connections, this is no longer necessary with the 6X. In addition, the VEGAPULS 6X has become even more intuitive. Commissioning is just a matter of a few mouse clicks. In many cases, customer-specific settings can already be entered into the instrument at the factory. Then it is just a matter of mounting and connecting.

The very latest radar sensor VEGAPULS 42 was developed on the basis of the VEGAPULS 6X and brings all the advantages to factory automation. The new sensor is based on the in-house developed 80 GHz radar chip, which is considered the best on the market due to its large dynamic range and versatile application possibilities.