Long-term stable pressure transmitters with ASIC

Paul Boughton

Trafag pressure transmitters are are suited to most requirements in very many of the harshest application areas. Apart from mature amplifier electronics – in the very latest products, equipped with ASIC – the technology of the associated pressure sensor is also of focal importance.

Special demands are placed particularly on signal processing by pressure transmitters.
Advantages in comparison with conventional electronics: 

  • Long-term drift <0.1percent FS.
  • Comprehensive compensation possibilities via three-dimensional sets of characteristic curves
  • Temperature range -40 to125°C.
  • Supports all prevalent sensor technologies (thin-film, thick-film, piezo-resistive).
  • Three independent input channels (pressure, temperature and one further digital auxiliary parameter).
  • Signals of only just a few mV can be processed without problem (ie free of drift).
  • The rectified output signals are available as pulse-width or pulse-density signals.

Using sputtering and CVD technologies, pressure sensitive thin film layers are deposited on the backside of a stainless steel membrane. The steel membrane is then welded to the pressure connection of a pressure transmitter to form a measuring cavity entirely made of stainless steel and free of O-ring. The complete assembly produces a very long-term stable signal and is highly temperature resistant. This offers:

  • Excellent long-term stability.
  • High temperature-resistance.
  • Completely weld-sealed sensor system made of stainless steel alloys.
  • No additional materials (eg O-rings) which could limit compatibility with certain sample media.
  • Withstands very high overpressures.
  • For gauge pressure ranges of 0–400mbar up to 0–2000bar. 

Trafag AG is based in Männedorf, Switzerland. www.trafag.com

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