Setra System Model 730 - Manual (Page 4)

1.0 Introduction
Setra’s Model 730 capacitance manometer is a temperature compensated,
absolute pressure transducer designed for accurate and repeatable vacu-
um measurements. Various full scale ranges are available from 10 Torr up
to 1000 Torr. The units of measurement may be specified in Torr (mmHg),
mBar, kPa, or PSIA.
The Model 730 operates from a 12-30 VDC power supply and provides
a 0-10 VDC signal output that is linear with pressure and independent of
gas composition. It can also be supplied with a 0-5 VDC output, which
operates from 9-30 VDC power supply. The Model 730 is pin for pin
compatible with competitive capacitance manometers. Superior
EMI/RFI performance is achieved by the use of a metal case in conjunc-
tion with surge and ESD suppression components and RFI filtering on the
inputs and outputs. The Model 730 has easy access to multi-turn
potentiometers for fine zero adjustments. Inconel is used for all wetted
materials for compatibility with corrosive gases. A wide range of process
connections are available.
The high accuracy pressure sensing element used in the Model 730 is
Setra’s patented variable capacitance sensor. A centrally located
feedthrough
assembly supports a circular electrode in close proximity to the back sur-
face of the diaphragm. Together, the electrode and diaphragm form a vari-
able capacitor within a small reference vacuum chamber. As the pressure
increases, the diaphragm deflects and the gap between the electrode and
diaphragm reduces, causing an increase in the capacitance. This change in
capacitance
is detected and converted to a highly accurate linear DC electronic signal
by Setra’s high frequency precision diode bridge circuit.
Excellent zero stability and barometric insensitivity is achieved through
the patented sensor design. The Model 730 sensor contains no fragile or
complex parts as found in ceramic based capacitance manometers. The all
welded construction eliminates stability issues inherent in other designs
due to frictional contact between dissimilar materials.
2.0 Mechanical Installation
Remove all packaging material and the protective flange cover and visually
check the Model 730. If the Model 730 appears damaged, notify Setra Sys-
tems or your supplier immediately. Retain packaging materials for inspec-
tion. Do not use if damaged. If the Model 730 is not going to be used
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