Flush mount pressure transmitters

Model 551 Pressure Transmitter

Model 551 Pressure Transmitter

551 is designed to provide rugged performance while measuring harsh corrosive materials. The sensor is a stainless steel machined diaphragm, with no oil fill. The zero cavity flush sensor provides an easy clean surface with no clogging. Magnetically coupled external adjustments prevent fluid ingress while providing a rangeable, field adjustable solution.


  Full Scale Pressure Ranges 0-50, 100, 150, 200, 250, 300, 500, 750, 1000, PSIG, PSIS, PSiA

Combined Linearity, Hysteresis and Repeatability

Full Scale Output (FSO) 16 mA at ±0.5% FSO
Resolution Infinite
Long Term Stability ≤±0.5% FSO
Pressure Connection Effect Zero Balance ≤±0.5% FSO
Mechanical & Eletrical Combined ≤0.1mSec
Temperature Effect on Zero ≤± 2% FSO per 100°F (37°C)
Temperature Effect on Span ≤± 2% FSO per 100°F (37°C)
Compensated Temperature Range 0°F to 185°F (-17°C to 85°C)
Operating Temperature Range -40°F to 250°F (-40°C to 121°C) -Process
-40°F to 185°F (-40°C to 85°C) -Ambient
Storage Temperature -40°F to 250°F (-40°C to 121°C)


Sensor Technology
Bonded foil strain gage
Supply Voltage
12 to 40 Vdc
Power Supply Regulation
≤±0.04% FSO per Volt
Output Signal 4 - 20 mA at 70°F (21°C)
Load Impedance 1400 Ohms max at 40 Vdc
Ripple ≤1% FSO
Zero Balance 4 mA ±0.5% FSO
Zero Adjustment

-50% FSPR (elevation) to 100% FSPR (suppression). Coarse and fine adjustments standard

Span Adjustment 5:1 turndown, externally
Range Calibration Signal 20% ±1% of FSPR, externally switched. The exact signal to pressure correlation is provided with each unit.
Circuit Protection Varistor protected across the input leads for surges above 38 V and currents to 250 Amps peak with a pulse width of 8-20 µSec. Reverse polarity protected
Bridge Resistance 5000 Ohms nominal
Insulation Resistance ≥ 2000 MegOhms at 50 Vdc
  RFI/EMI Suppression ≤1% FSO output change at 30 V/meter, 10-1000 Mhz
  Electrical Connection 1/2” NPT male conduit, 3 wires, 18 AWG, 36”L
  Wire Color Codes

Red + Power/Signal

Black - Power/Signal

Green Case Ground


Enclosure Materials
304 and 316 stainless steel
Wetted Parts
17-4PH NACE (Inconel X750 optional)
  Weight 22 oz
  Identification Laser etched onto body


Pressure Connection
M44 X 1.25 fitting
Proof Pressure
1.5 times rated range
Burst Pressure
≥ 3 times rated range or max range of clamp and tubing, whichever is less
Identification Laser etched onto bod
Measured Fluids Any gas or liquid compatible with 17-4PH NACE
Enclosure Classification .NEMA 4X, 5, 6, 12


  Alternate Connectors  
BZ Micro change connector
ZP 6-pin hermetic (Bendix style)
  Performance Options  
DG Improved temperature compensation
DH Special range (550 only)
EA Special calibration
JJ Direct mount indicator with Explosion Proof housing
JS Direct mount indicator
NH Customer specified identification
PW 1/8 DIN digital indicator
QB Inconel wetted parts
TW Russia Intrinsic Safety