Pressure Measurement

High Purity Pressure Transducer


GCT225 high purity pressure transmitter


Setra’s Model GCT225 Series is ideal for pressure measurement applications that require exceptional insensitivity to environmental extremes. The GCT225 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 GCT225 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
Hysteresis0.20% FS
Non-Repeatability0.02% 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 Pressure2.0 (1.8)
OverpressureMass 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

CaseStainless Steel
Electrical Connection6ft./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
VentThrough Cover
Internal Cavity Volume0.11 in.3
Wetted MaterialVAR 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