New Hart Loop Converter Increases the Performance of 4…20 mA Field Devices

Related Vendors

DÜPERTHAL Sicherheitstechnik GmbH & Co. KG

TURCK GmbH

Anton Paar GmbH

Pepperl+Fuchs SE

Real-time corrosion monitoring

The combination of the Hart Loop Converter with an online corrosion transmitter illustrates the new opportunities available to the operator. CorrTran MV from Pepperl+Fuchs is the first 2-wire 4…20 mA transmitter with Hart protocol that simultaneously evaluates general and localized corrosion (pitting). Why is this so important?

Corrosion causes enormous damage in plants and facilities. Steam generators in particular are exposed to these expensive effects. The pure water required is not just corrosive to steam generators and condensate systems; it can cause leaks that result in unwelcome chemicals entering the process and further increasing the potential of corrosion.

With CorrTran MV, it is possible to monitor the corrosion behavior in real time and react to it before more damage occurs. This means that corrosion analysis has been moved out of the laboratory and into daily process control: a new approach for monitoring corrosion in real time. Therefore, the operator is in a position to monitor the process optimally in the framework of predictive maintenance.

The central elements of CorrTran MV are modern, patented algorithms and data analyses, which measure general corrosion rates and localized corrosion (pitting). To determine the general corrosion rate, the measurement of linear polarization resistance is used. In addition, during a measuring cycle, the corrosion sensor carries out an electrochemical noise measurement which allows a measurement of pitting. At the end of each cycle, the corrosion rate and pitting value are calculated and made available to plant personnel in the form of a 4…20 mA signal via Hart. The Hart Loop Converter expands the analog process information with the additional data in the Hart variables.

Summary: The operator has the opportunity to expand the potential of new and installed Hart devices with the Hart Loop Converter from Pepperl+Fuchs. The HLC is suitable for measurements such as mass flow rate, temperature and pressure, as well as for positioners or the CorrTran MV online corrosion transmitter. So, with limited extra effort, more comprehensive measurement and diagnosis information is available to the user — all via a 2-wire cable.

* The author is Product Marketing Manager Interface Technology, Division Process Automation, Pepperl+Fuchs GmbH, Mannheim/Germany

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