There is consensus among level measurement experts that only two technologies are suitable for monitoring and controlling inventory in liquid storage tanks: radar and servo-operated. Even so, within these technologies there are options designed to meet process measurements, whose variable of interest is the level itself, and options designed to meet inventory measurements, in which the variable of interest is the amount of product stored.
With the improvement in accuracies achieved in the laboratory by process radars (pulse type), more and more users end up hooked by the low cost of this equipment, and think of this technology as an economical solution for automation and monitoring of their tank park.
However, while under controlled laboratory conditions pulsed radars reach accuracies in the millimeter range, when installed in the field the errors are found in the centimeter range.
One of the factors that influence this performance drop is the quality of the electronics used to generate the radar signal. When analog components are used to generate the signal, a lower cost is achieved in the manufacture of the equipment, however, the stability of the signal generation is affected and the radar begins to present measurement errors due to the variation of the ambient temperature. .
It is important to note that this influence can be so high that just the temperature variation over the same service day is enough to generate a non-conformity. Thus, the use of inappropriate technology can end up leading the user to wrong management decisions and increasing problems for which automation was originally intended to solve.
Thus, in addition to the OIML R 85 certification, it is always recommended to check that the radar signal is generated with digital 100% components, so that its measurement is not interfered with by variations in ambient temperature. Another tip to reduce the chances of being negatively surprised is, whenever possible, to look for the references of the equipment model in similar applications.
Fluxo has experience in the implementation of telemetry systems in more than 4 thousand tanks and is the exclusive distributor of Honeywell Enraf in Brazil. Honeywel Enraf is the world market leader in level gauge applications (radar and servo operated) for inventory control, with uncertainties starting at +/-0.4mm.