Two New Instrument Families Operate Under Pressure

Product Exclusive: New Pressure Transmitters Offer Forward Thinking and Unique Features

The proliferation of industrial communications protocols on plant floors can create problems for those of you who build and support turnkey automated process equipment skids.

 

Do you have to stock a variety pressure transducers that speak HART and Profibus and Foundation fieldbus? What about field changes? It certainly would be helpful if you could swap out components such as the display or sensor modules at the user site.

 

Endress+Hauser thinks it can be of service. The company introduced the Cerabar and Deltabar families of pressure transmitters with features that provide HART, Profibus and Foundation fieldbus capability by means of interchangeable circuit card inserts. In addition, the modular design of these pressure transmitters provides the ability to replace the display, electronics module, and sensor modules in the field.

 

"Our Cerabar S pressure transmitter is suitable for gauge and absolute pressure measurement in gases, liquids or steam in all areas of process engineering," says Scott Richardson, Endress+Hauser's pressure product manager. "It handles level or volume measurement in liquids."

 

The Cerabar S offers a choice of capacitative sensor and ceramic membrane; monosilicon-based sensor and welded metallic membrane or diaphragm seal, and a high-temperature version without the diaphragm seal. The Cerabar S capacitive ceramic sensor technology is unique, says Richardson, and is designed specifically for corrosive or abrasive applications. The measuring cell is a 99.9% pure aluminum-oxide sensor. Alumina ceramic sensors have improved reliability and corrosion resistance in highly aggressive media, most chemicals, acids, and bases. The ceramic sensor handles temperatures to 300° F, but one version with a 316 SS membrane and no diaphragm seal is designed for temperature measurement to 360° F. "This design eliminates zero-shift due to ambient/process temperature differential," say Richardson. "The sensors permit virtually no hydrogen permeation and are so durable they can be cleaned with a wire brush."

 

The Deltabar S differential pressure transmitters were designed specifically for differential pressure, flow and level applications and include the same capacitive ceramic sensor technology. "The monosilicon-based sensor with metal membranes provides the fastest response time on the market of any digital transmitter," claims Richardson. "This allows process changes to be visible more quickly and eliminates lag time."

 

In addition, flow functionality is built right into the transmitter, eliminating the necessity for a separate flow computer. The Deltabar differential pressure flow transmitter permits bidirectional flow, has a low-flow cutoff, and dual totalizers for counting daily/weekly/annual flow.

 

"The Cerabar S and Deltabar S are unique to the market," claims Richardson. "Transmitters are available with pushbuttons to do complete configuration at the transmitter. The external pushbuttons can be used without opening the housing."