New meters use an innovative man-machine interface with powerful communications and control functions to combine simplicity of operation with easy access to process and diagnostic information
Innovative display and MMI for new PH and conductivity analysers reduce commissioning and operating costs The new EXA450 series from Yokogawa is a family of pH and conductivity analysers that combine a versatile new MMI (man-machine interface) with powerful communications and control functions.
The instrument is housed in a rugged and watertight field housing measuring 144x144x144mm, which is compatible in size, mounting arrangement and termination detail with Yokogawa's earlier EXA400 and EXA402 series, making it a very straightforward task for existing users to upgrade their installations.
The new man-machine interface uses a backlit grey-scale dot-matrix LCD display which combines simplicity of operation with easy access to process and diagnostic information.
Commissioning and maintenance time is reduced, and an instruction manual is unnecessary, because all information is displayed in plain, easy-to-understand text with no abbreviated words or coded messages.
The MMI is operated via context-sensitive buttons on a robust membrane-protected touch-sensitive screen that also displays measured variables, tag number and descriptive text in one of five different languages.
The field enclosure, which is equally suited to panel, pipe or wall mounting, is truly watertight, and is independently certified by KEMA to meet IP66 and NEMA4X requirements against water and dust.
The EXA450 family includes three four-wire models: the PH450G pH/ORP analyser; SC450G conductivity/resistivity analyser; and ISC450G inductive conductivity analyser.
High accuracy and integrity are guaranteed with all variants using advanced temperature compensation algorithms and dynamic sensor checking that ensures excellent reliability and repeatability.
The temperature compensation function of the pH meter has significant benefit in pure water applications that are common in the power generation industry where the dissociation of water molecules can introduce temperature related discrepancies between field and laboratory test results.
Other features include pre-defined buffer solutions, three sets of pre-loaded pH buffer standards, a trending display for up to two weeks of data, and on-screen logbooks for the storage of calibration data, configuration changes and events.
In addition to two mA current outputs and four SPDT relay contacts, each instrument features HART communications.
Both DT and DTM files are available for direct connection to HART handheld terminals, HIM monitors and the Pactware PC configurator.
Full P, PI and PID control is available on all outputs, and an integral wash function is included.
Each EXA450 analyser is supplied complete with a stainless steel nameplate, a quality inspection certificate and tag plate (with no text).
