Model 551

SKU: 551

Pressure Transmitter, Compact Size

The Delta Controls Model 551 Pressure Transmitter incorporates both the sensor and the electronics in a module mounted in a heavy duty body. Its compact size makes it ideal for very limited space conditions.

The sensor includes an oil filled 316-L S.S. or Hastelloy”C”® diaphragm which isolates the strain gage bridge from the process liquid or gas. The back of the sensor is usually vented to atmosphere to compensate for barometric pressure changes.


  • Small Size For Tight Places
  • Two Wire Loop Powered
  • 4-20 mADC
  • Integral Electronics/Sensor Module; Potted for Corrosive Locations
  • Surface Mount Silicon Electronics
  • Used For Pressure Or Level Measurement
  • NPT, ANSI, DIN, or JIS Process Connection
  • Ranges From 12 Inches Water To 1000 PSI (0.3 to 70 Bar)
  • Zero & Span Pots For Field Recalibration
  • Spark & Voltage Surge Protection
  • Maintenance Free Operation


  • Technology: Silicon Strain gage.
  • Supply Power: 13 to 35 VDC, 2 Wire loop powered
  • Output: 4-20 mADC isolated, Intrinsically Safe
  • Loop Impedance: 550 ohms @ 24 VDC, 1100 ohms @ 35 VDC
  • Adjustments: Span from 30% to 100% of sensor range, Zero to 30% basic and to 80% optionally, non-interactive.
  • Over Pressure: 2X Range (35 PSI, 2.5 Bar min) without damage, 3X Range (1000 PSI / 70 Bar min) without rupture minimum
  • Temperature Range:
    • -20 to +220°F (-30 to +105°C) Process
    • -20 to +185°F (-30 to +85°C) Electronics
    • 30 to +180°F (-1 to +65°C) Compensated (Higher Available)
  • Accuracy: ± 0.25% F.S. or better
  • Thermal Error: ± 0.02% F.S./ °F. maximum
  • Barometric Effect: None


The Delta Controls Model 551 is used to measure and transmit the pressure of liquids and gases in pipelines, tanks, ducts and other containments. The 551 is commonly used as a liquid level transmitter in vented tanks. The pressure at the bottom of a vented tank containing a liquid is linearly proportional to the height and density of the liquid.

Optional Features

  • ½" NPTM condensate pigtail for steam service.

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