Expert’s Answer: Smar LD300

Hey! Before I answer your question directly, I would like to remind our readers of some important information. The Smar LD300 series is a differential pressure transmitter device. This means that it gets the pressure of two points and calculates the difference between them. Unlike a gauge or an absolute pressure transmitter, there is no built-in reference pressure. As we will discuss in this article, you can use DP transmitters to measure different variables that are related to pressure. This includes level, flow, velocity or density of a fluid.

Short Answer: Yes

So, getting back to your question. Yes, you can use the same device to measure flow and level. However, it is important to consider some adjustments you have to make in order to get a proper reading.

Level Measurement

When it comes to level measurement it is important to set your references. If you do not set your references correctly the device cannot calculate your variable properly. There are different ways to calculate it depending on how you install your device. But don’t panic, we have a step by step explanation in our articles about level measurement using DP transmitter on open and closed tanks. When you have your 0% level and 100% level calculated you should set it on your device.

Courtesy of SMAR

Flow Measurement

Regarding flow measurement, you will need a primary element installed in conjunction with your LD300 series. And guess what, we also explain all about flow measurement using DP transmitters in another article. First thing is to get your setup ready with your transmitter and primary element installed. Next, it is time to configure your device to show the measuring unit properly.

The goal here is to measure flow with the data you collect from the pressure. You can calculate the flow by taking the square root of the differential pressure value. In this case, you will need to set your device transfer function to square root instead of linear. There is also the possibility to set a cut off on flow measurement applications. In this way, your device doesn’t give you false reading when the flow is very low or there is a noise disturbance.

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