227 Ultra High Purity Pressure Transducer

Setra's Model 227 transducer is designed for high density, modular block gas sticks and panels required for today’s 300 mm tools. The Model 227s 1-1/8’’ footprint optimizes valuable space, and its rugged design makes it ideal for pressure measurements that require long-term stability, high accuracy and exceptional insensitivity to environmental extremes.

Unlike many other designs with large deadended cavity volume, the 227 has a small swept sensor chamber for easy purgeability. All wetted parts are 316L VIM/VAR stainless steel passivated to 5 Ra (7 Ra. max.) fi nish, which eliminates surface irregularities and provides the proper surface chemistry for corrosion resistance, assuring contaminant-free gas distribution.

Available wtih 5 VDC, 10 VDC, or 4 to 20 mA ouput, the Model 227 offers ±0.25% Full Scale or ±1.0% of Reading accuracy. The Model 227 comes with a space-saving1-1/8” C-Seal or W-Seal downmount interfacing base with choice of a multi-conductor cable, 4-pin bayonet connector, and 9 or 15 pin D-sub connector for electrical termination. When coupled with the Model 327 1–1/8’’ rotatable display, this package provides the ultimate in pressure measurement and display. Side access to the zero and span adjustments beneath the rotating protective cover, and choice of absolute, gauge or compound pressure ranges complete this unique design.

Principle of Operation

Setra’s patented variable capacitance sensor features a 316L stainless steel diaphragm and an insulated electrode plate. A variable capacitor is formed between the sensor body and the electrode plate. An increase in pressure causes a slight rounding of the diaphragm, which decreases the capacitance. The capacitance change is detected and converted to a highly accurate linear DC electric signal by Setra’s unique custom integrated circuit, utilizing a patented charge balance principle. Setra’s entire Ultra-High Purity series is based on Setra’s proven capacitive sensing technology with highly accurate and stable voltage or current output signals that are virtually EMI/RFI immune.