Inficon PGE500, Operating Manual, Page: 9 / 84

tinb21e1 (2016-06)
9
1 Introduction / General Information
1.1 Description
Thermal conductivity gauges measure pressure indirectly by
sensing the loss of heat from a sensor to the surrounding gases.
The higher the pressure of the surrounding gas, the more heat is
conducted away from the sensor. Pirani thermal conductivity
gauges maintain a sensor (usually a wire) at some constant tem-
perature, and measure the current or power required to maintain
that temperature. A standard Pirani gauge has a useful measur-
ing range of about 10
-4
Torr to 10 Torr. By taking advantage of
convection currents that are generated above 1 Torr, convection-
enhanced Pirani gauges increase the measuring range to just
above atmosphere.
The INFICON PGE500 Pirani Gauge Enhanced module provides
the basic signal conditioning required to turn a convection
vacuum gauge into a complete measuring instrument. The mod-
ule provides linear, non-linear or log-linear analog outputs, two
setpoint relays and RS232/485 serial communications. In addi-
tion, a built-in display provides a convenient user interface for
setup and operation of the vacuum gauge.
1.2 Specifications
Measurement range
1.3×10
-4
… 1333 mbar
1×10
-4
… 1000 Torr
1.3×10
-2
Pa … 133 kPa
Accuracy - N
2
(typical)
1.3×10
-4
… 1.3×10
-3
mbar
1.3×10
-3
… 530 mbar
530 … 1333 mbar
0.1 ×10
-3
mbar resolution
±10% of reading
±2.5% of reading
1×10
-4
… 1×10
-3
Torr
1×10
-3
… 400 Torr
400 … 1000 Torr
0.1 mTorr resolution
±10% of reading
±2.5% of reading
Repeatability - N
2
(typical) ±2% of reading