High Purity Pressure Transducer – Model GCT 225



Setra’s Model GCT-225 Series is idealfor pressure measurement applications that require exceptional insensitivity to environmental extremes. The GCT-225 is insensitive to factors such as torque effect on the fitting, temperature transients, and RFI effects generated by other instruments and equipment.

Designed with a low cavity volume of 0.11 in3, the GCT-225 can be easily purged. All wetted parts are high quality VAR 316L SS, electropolished to 7 Ra (10 max.) finish, and every sensor is mass spectrometer helium leak tested to 1 x 10-9 ATM.CC/sec.

In a typical Setra configuration, a compact housing contains two closely-spaced, parallel, electrically-isolated metallic surfaces, one of which is essentially a diaphragm capable of slight flexing under applied pressure. The diaphragm is constructed of low-hysteresis material such as 17-4 PH SS or a proprietary compound of fused glass and ceramic (Setraceramâ„¢). These firmly secured surfaces (or plates) are mounted so that a slight mechanical flexing of the assembly, caused by a minute change in applied pressure, alters the gap between them (creating, in effect, a variable capacitor). The resulting change in capacitance is detected by a sensitive linear comparator circuit (employing proprietary, custom-designed ASICs), which amplifies and outputs a proportional, high-level signal.


  • Superior stability avoids downtime
  • EMI/RFI immunity prevents false shutdown
  • Sturdy design allows trouble-free installation
  • Meets CE conformance standards
  • Gas Cabinets
  • High Purity Gas Delivery Systems
  • Semiconductor Process Tools
Technical Details
Accuracy* RSS (At Constant Temp.) ±0.25% FS
Non-Linearity, BFSL ±0.15% FS
Hysteresis 0.20% FS
Non-Repeatability 0.02% FS
Thermal Effects**
Compensated Range °F(°C) 0 to +150 (-18 to +65)
Zero/Span Shift %FS/°F(°C) 0.033 (0.06)
Maximum Line Pressure 2.0 (1.8)
Overpressure Mass Spectrometer Helium Leak
Tested to 1 x 10-9 ATM CC/Sec.
* RSS of Non-Linearity, Non-Repeatability and Hysteresis.
**Units calibrated at nominal 70°F. Maximum thermal error computed from this datum.
Physical Description
Case Stainless Steel
Electrical Connection 6ft./1.8m Multiconductor
Cable or 4-Pin Bayonet Connector
Pressure Fitting #4 Face Seal Swivel Male or Female,
1/4" NPT Male, or Tube Stub
Vent Through Cover
Internal Cavity Volume 0.11 in.3
Wetted Material VAR 316L SS Electropolished to
7 RA (10 max.) Finish
Weight (Approximate) 4 ounces (113 grams)
Environmental Data
Operating* °F (°C) -40 to +185 (-40 to +85)
Storage °F (°C) -40 to +185 (-40 to +85)
*Operating temperature limits of the electronics only. Pressure media temperatures may be considerably higher or lower.
Note: Specification are subject to change without notice.

Note: Specification are subject to change without notice

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