VEGA has a lot of choices when it comes to radar level measurement devices. In general, there are two families of sensors from which to choose, the Pro Series and the Basic Series. The Pro Series is a full-featured sensor. The Basic Series is a lower priced, very capable sensor. The intent of this piece is to explain why one would choose one over the other.
The simplest reason to use a Pro Series device instead of a Basic Series is that the Basic Series sensor does not meet the requirements of the installation. This could be something as simple as the temperature and pressure of the vessel in which the sensor is to be installed. The Basic Series has a temperature range of -40 F to 176 F and a pressure range of full vacuum up to 43.5 psi. If the temperature and pressure are outside of this, then the Pro Series may meet the needs (-320 F to 842 F, full vacuum up to 2320 psi).
There are some certifications that are only available in the Pro Series. Functional Safety (SIL) and cyber security (IEC 62433) certifications are two of these. While both the Pro and Basic Series devices can be used in electrically hazardous areas, only the Pro Series is available with explosion proof as the protection method.
While 4…20 mA/HART is the most common output that is used for Pro and Basic Series radars there are some outputs that are unique to each. For instance, SDI-12, which is used in the Hydrologic market is available exclusively in the Basic Series.
The Pro Series has many more options when it comes to the materials of construction and wetted parts. The Pro Series offers plastic, stainless steel, and aluminum housings. Stainless steel, Hastelloy C, Duplex, Monel, PFA, PTFE, PEEK and other materials are available as wetted. The Basic Series has PVDF wetted parts and a plastic housing. Installations in which PVDF is not acceptable require the use of the Pro Series.
From a mechanical ruggedness standpoint, the Basic Series is constructed of all plastic parts while the Pro-series has metal process connections, antennas, and housings available.
The Pro Series Radar has advantages when it comes to measuring performance. It is more accurate (+/- 1mm vs +/- 2 mm or 5mm). It is also slightly faster as it updates the output once every 200ms as opposed to once per 250ms. The Basic Series has a measurement range limit of 30 meters. The Pro Series can measure as far as 120 meters. Overall, the Pro Series is faster, more accurate, and can measure further.
The Basic Series is limited in its available antennas. The Pro Series has larger antennas available, with a narrower beam, as well as smaller antennas available for mounting in small vessels with small process connections. The Pro Series has a version specifically designed for use in solids. It has a swivel mount integrated into the mounting flange. This allows one to aim the measurement to the position in the silo that provides the most useful measurement. In other words, it could be on the high end near the position directly underneath the fill or the low side when directly above the emptying point. This version also has an air purge which can help with preventing build-up on the antenna.
The Basic Series radar has an available version with a submersible (IP68 3 bar, 24 h) housing and integral cable. This would be the first choice of sensor it if were to be mounted in an area, like a lift station or sump, where it is possible to become covered in water.
While it is not usually one of the factors that goes into choosing which radar to use, the Pro Series radar has an entire suite of diagnostic tools that are not available in the Basic Series. These include on board trending, echo curve recording, event memory with real time clock, and a host of others. These can be very useful when tackling difficult measurements or diagnosing customer process problems.
VEGA has radar sensors that can perform in many demanding environments including extreme heat and cold, high pressure, chemically corrosive, and potentially explosive. However, there are times when having this capability is not needed. That is when the Basic Series radar should be used. The Basic Series allows one to enjoy all the benefits of radar, without having to pay for features that are either not wanted or not needed. At the same time, there are some environments that require some one or more of the features offered by the Pro Series. In general, it is recommended to use the sensor that will perform the job and survive the environment, providing a long-term, economical solution.