4 minute read
Towards a universal radar
JÜRGEN SKOWAISA, VEGA RADAR PRODUCT MANAGER, SPEAKS WITH ROADS & INFRASTRUCTURE ABOUT THE POSSIBILITY FOR A UNIVERSAL LEVEL RADAR SENSOR.
As cities and their infrastructure face growing shocks and stresses, ranging from environmental and economic to social and digital, the notion of resilient cities is gaining traction. The concept, broadly, refers to cities with the ability to absorb, recover and prepare for future shocks.
While this certainly extends beyond transport infrastructure, as the mobility framework of most cities, building and maintaining roads is a crucial element of the resilient cities’ concept. As such, Jürgen Skowaisa, VEGA Radar Product Manager, says achieving a resilient city requires construction companies and material manufacturers to prioritise harmonisation and safety.
Mr. Skowaisa says that when universal standards exist for level measurement, the chemical and material composition of bitumen and bulk solids can be more easily understood. He says that this understanding enhances safety and minimises the potential for poorly produced mixes or even tank explosions. To that end, Mr. Skowaisa says VEGA is working towards developing a near universal radar sensor.
The development of radar level measuring instruments has a documented history, Mr. Skowaisa says, largely superseding previous measuring principles such as electromechanical sounding systems or ultrasonic instruments.
“Application areas have gradually expanded, meaning users have increasing access to the technology. However, according to the opinion of many stakeholders, a measuring instrument that really covers all applications has not yet been seen,” he says.
“That said, thanks to higher frequency ranges and new instrument versions, the VEGAPULS 69 comes very close to that ideal.”
Non-contact radar technology is characterised by particularly high measurement accuracy.
“The measurement is not affected by changing medium properties or process conditions such as temperature, pressure or intense dust generation. User-friendly adjustment without vessel filling and emptying saves time, and the sensors are maintenance-free,” he says.
The VEGAPULS 69 operates at a 79-gigahertz frequency, Mr. Skowaisa says, enabling higher transmission signal focusing. He adds that high-level focusing helps to better separate the actual measuring signal from interference signals.
“The opening angle of the radiated radar energy, and therefore the focusing, depends on two factors: the transmission frequency and the active antenna area. This means much better focusing is achieved at a higher frequency with the same antenna size,” Mr. Skowaisa says.
“With new microwave components, even the slightest reflection signals can be measured, meaning products with poor reflection properties, which were previously difficult to measure, can now be measured reliably.”
He adds that this works to circumnavigate a number of measurement interference issues, creating a sensor of widespread, almost universal, application.
According to Mr. Skowaisa, the instrument emits a continuous radar signal via its lens-shaped antenna. The signal is then frequency modulated with a sawtooth form.
“The emitted signal is reflected by the medium and received by the antenna as an echo. The frequency of the received signal always deviates from the actual emitted frequency,” he says.
“The frequency difference is then calculated by special algorithms in the sensor electronics proportional to the level in the vessel.”
Furthermore, the VEGAPULS 69 operates with low emitted power in the W-band frequency range, facilitating the added value of energy efficiency.
With a measuring range up to 120 metres and an accuracy of five millimetres plus, the VEGAPULS 69 has enough power reserves even for unusual assignments, Mr. Skowaisa says, such as silo shafts or distance measurement in conveyor systems.
While Mr. Skowaisa cautions that there is still no “universal” sensor, he says the VEGAPULS 69 can be used both for continuous level measurement and as a limit level switch.
“In the former application, the filling height is measured and transformed into a level proportional signal that is either displayed directly or is processed in a control system,” he says.
“In point level detection, on the other hand, the filling heights are measured at a fixed point and transformed into a switching command.”
The sensor’s antenna system, Mr. Skowaisa says, is made of the robust material PEEK, which has high temperature and chemical resistance to facilitate multiple and varied applications.
“Its lens antenna is also non-sensitive to build-up and dirt and shows no signs of wear. Another great advantage in infrastructure applications is that the 80-gigahertz microwaves easily penetrate dense clouds of gas or dust,” he says.
“Since the sensor has a flushing air connection as a standard feature, it can clean itself quickly at any time and ‘dispose’ of any build-up. Even in difficult applications, the VEGAPULS 69 is completely unaffected by material deposits on the antenna.”
Mr. Skowaisa adds that the switching command can be used either to stop or start in filling systems such as conveyor belts, rotary valves and pneumatic conveyors, or for further processing in process control systems. As with all VEGA products, the VEGAPULS 69 has full wireless capabilities via the VEGA tools app and optional display and adjustment module PLICSCOM.
“PLICSCOM is used for measured value indication, adjustment and diagnosis directly on the sensor. Its simple menu structure enables quick setup, with status messages displayed in plain text. The optional Bluetooth feature also allows for wireless operation,” Mr. Skowaisa says.
“The app also supports fast setup and easy maintenance, in addition to convenient visualisation of current level and pressure data for any application: a further layer of simplicity, or in my opinion, universality.”
