PMC21 datasheet(8/48 Pages) EH

8 / 48 page

Cerabar PMC11, PMC21, PMP11, PMP21

Endress+Hauser

Function and system design

Measuring principle -

process pressure

measurement

Devices with ceramic process isolating diaphragm (Ceraphire®)

The ceramic sensor is an oil-free sensor, i.e. the process pressure acts directly on the robust ceramic

process isolating diaphragm and causes it to deflect. A pressure-dependent change in capacitance is

measured at the electrodes of the ceramic substrate and the process isolating diaphragm. The

measuring range is determined by the thickness of the ceramic process isolating diaphragm.

Advantages:

• Guaranteed overload resistance up to 40 times the nominal pressure

• The ultrapure 99.9% ceramic (Ceraphire®, see also "www.endress.com/ceraphire") ensures:

• Extremely high chemical durability

• High mechanical durability

• Can be used in absolute vacuum

• Small measuring ranges

A0020465

Air pressure (gauge pressure sensors)

Ceramic substrate

Electrodes

Ceramic process isolating diaphragm

Devices with metallic process isolating diaphragm

The process pressure deflects the metal process isolating diaphragm of the sensor and a fill fluid

transfers the pressure to a Wheatstone bridge (semiconductor technology). The pressure-dependent

change in the bridge output voltage is measured and evaluated.

Advantages:

• Can be used for high process pressures

• Fully welded sensor

• Slim, flush-mounted process connections available

A0016448

Silicon measuring element, substrate

Wheatstone bridge

Channel with fill fluid

Metal process isolating diaphragm

Measuring system

A complete measuring system comprises:

PMC21 Datasheet(PDF) 8 Page - Endress+Hauser Group Services AG