Expert’s Answer: Units available Smar LD400

Very good choice. The Smar LD400 is a great differential pressure transmitter that can be used in many different applications. Not only for pressure and flow, but also for level measurement, volume, mass flow and so on. Keep in mind, each application requires different installations and setup. At this point, if you have any questions about what you can do with differential pressure transmitters we have a guide available for you.

Flow Measurement

When it comes to volumetric flow measurement the Smar LD400 has a wide range of units. It is important point out that the units are calculated based on a reference unit and then converted to the desired unit. For the Smar LD400 this unit is H²O at 20° Celsius. In any event, if you wanna know more about the conversion factors you can have a look at the page 56 of the technical manual.

Another factor to consider is the display size. LD400 has a 4 1/2 digit display, which means that the largest value shown would be 19999. As a result, any value above this will not be visible. Therefore choose your units accordingly.

Moreover, it is important to remember that in flow measurement we don’t use linear differential pressure. This is because the flow calculation is related to the square root of the differential pressure value. Therefore, you will need to configure your device to have a square root transfer function. If you don’t know how to do it we can teach you in another article. But it is important to stress that if you don’t set it up properly you will get a wrong reading from your transmitter.

Available Units

Now to answer your question, here is a list of what units are available for volumetric flow measurement on the Smar LD400:

  • ft3 /min
  • gal/min
  • Gal/min
  • m3 /h
  • gal/s
  • I/s
  • MI/d
  • ft3 /d
  • m3 /s
  • m/d
  • Ga/h
  • Ga/d
  • ft3 / h
  • m3 /min
  • bbl/s
  • bbl/min
  • bbl/d
  • gal/s
  • I/h
  • gal/d


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