Introduction; About This Guide; Basics Of Lwt Level Measurement - ABB LWT300 series User Manual

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Introduction

The LWT series of instruments are microprocessor-based level transmitters that use very low power
microwave energy to determine the level of the product being measured. A rod or cable "probe" is hung
into the vessel to act as a waveguide, i.e. microwave energy stays concentrated around the length of the
probe instead of being dispersed, as it would be if there was no probe.

About this guide

This user guide is intended for personnel using LWT series instruments for routine monitoring. It
contains installation, usage, maintenance, and troubleshooting instructions.
Read this guide carefully before working with the instrument. For personnel and system safety, and
for optimum performance, make sure that you thoroughly understand the contents of this document
before installing, using or maintaining the instrument. This guide does not contain detailed information
on all available models or every conceivable event that may occur during setup, operation, and
maintenance work.

Basics of LWT level measurement

The instrument electronics housing (a.k.a. "the head") is fitted with a special adapter (the coupler)
that serves as a connection between the head and the process in which measurements will be taken.
A rod or cable (the probe) hangs from the coupler into the product being measured (see Figure 1 on
page 8).