Expert’s answer: Difference between electronic and conventional DP transmitters
Okay, good question. Both will measure level with a good degree of accuracy, depending on your process and setup. However, vendors created electronic differential pressure (DP) transmitters address some problems with the standard devices. Will they help you? Maybe, but maybe not.
Let me point out the most relevant differences between these technologies here. If you want more details on electronic DP transmitters, then read our article “Electronic differential pressure transmitters and why we love them.”
To measure level with a DP transmitter, you need compensation of the pressure, gas, or vapor on the top of the tank. So you’ll connect the low-pressure input of the transmitter there. On top of that, you can have two different installs for the impulse lines called wet and dry legs; you can read more about these methods here.
However, sometimes these installations run into problems. The wet leg can have issues with leaks and ice, and the dry leg can have problems with condensation. All of these issues can affect the measurement.
To solve these problems, you could deploy a DP transmitter with a capillary. However, this solution brings its own issues! A change in the ambient temperature can change the density of the filled liquid. This difference can also affect the measurement.
So a few companies worked on those problems, and the electronic DP transmitter hit the market to solve all of them. Solutions vary by vendor, with some using two smart devices talking to each other and others using a transmitter with an external digital sensor.
Therefore, to decide which would work best for you, standard or electronic, you should examine your process to see if it could potentially create the problems we pointed out. If not, then you’ll probably save money with the standard option. If so, then you may want to consider shelling out for the electronic version.