Endress+Hauser Cerabar M PMC41 - Measuring Principle

Cerabar M
Endress+Hauser 7
Measuring principle
Ceramic measuring diaphragm used for PMC41 and PMC45 (Ceraphire
®
)
The ceramic sensor is a dry sensor, i.e. the process pressure acts directly on the robust ceramic diaphragm and
deflects it. A pressure-dependent change in capacitance is measured at the electrodes of the ceramic carrier and
the diaphragm. The measuring range is determined by the thickness of the ceramic diaphragm.
Advantages:
• Guaranteed overload resistance up to 40 times the nominal pressure (max. 60 bar)
• Thanks to 99.9% high-purity ceramic (Ceraphire
®
, → see also www.endress.com/ceraphire)
– Extremely high chemical stability
– Less relaxation
– High mechanical stability
• Suitable for vacuums
• Very suitable for hygienic processes as the ceramic material Al
2
O
3
is safe and not harmful to health
(FDA 21CFR186.1256, USP Class VI)
Metal measuring diaphragm used for PMP41, PMP45, PMP46 and PMP48
PMP41 and PMP45
The operating pressure deflects the separating diaphragm and a fill fluid transfers the pressure to a resistance
measuring bridge (semiconductor technology). The pressure-dependent change in the bridge output voltage is
measured and processed further.
Advantages:
• Can be used with process pressures up to 400 bar
• High long-term stability
• Guaranteed overload resistance up to 4 times the nominal pressure (max. 600 bar)
• Compact solution even for small hygienic connections
PMP46 and PMP48
The operating pressure acts on the diaphragm of the diaphragm seal and is transferred to the separating
diaphragm of the sensor by a diaphragm seal fill fluid. The separating diaphragm is deflected and a fill fluid
transfers the pressure to a resistance measuring bridge. The pressure-dependent change in the bridge output
voltage is measured and processed further.
Advantages:
• Can be used with process pressures up to 400 bar
• High long-term stability
• Guaranteed overload resistance up to 4 times the nominal pressure (max. 600 bar)
Ceramic measuring diaphragm used for PMC41 and PMC45
(Ceraphire
®
)
Metal measuring diaphragm used in
PMP41, PMP45, PMP46 and PMP48
P01-PMC71xxx-03-xx-xx-xx-000
Ceramic sensor
➀ Air pressure (overpressure sensors)
➁ Ceramic carrier
➂ Electrodes
➃ Ceramic diaphragm
P01-PMP4xxxx-03-xx-xx-xx-000
Metal sensor
➀ Silicon measuring element, carrier
➁ Measuring diaphragm with Wheatstone bridge
➂ Channel with fill fluid
➃ Flush-mounted metal diaphragm
p
➃
➂➀➁
➂
➀
➁
p
➃