Scenario 1: Measurement Without Enabling The Process Pressure Feature; Measuring Dew Point - GE Optica Operator's Manual

3.6.4 Scenario 1: Measurement Without Enabling the Process Pressure Feature

Process pressure is 100 psi, within the range of a typical GE chilled mirror sensor. Since vapor pressure and dew point
are pressure-dependent, a flow meter is installed downstream of the sensor to assure that the sensor cavity is at the
process pressure (see Figure 26 below).
3.6.4a Measuring Vapor Pressure Without a Pressure Sensor
To measure vapor pressure without a pressure sensor, make the following entries in the Pressure Input menu section for
this example:
•
Input: Use Default
•
Units: psia
•
Default: 100
•
Process Status: Disabled
3.6.4b Measuring Vapor Pressure With a Pressure Sensor
To measure vapor pressure with a 4-20 mA, 0-30 psia pressure sensor, connect the sensor to the Optica's terminal block
and make the following entries in the Pressure Input menu:
•
Input: In 4-20
•
Units: psia
•
Upper: 30.00
•
Lower: 0.00
•
Process Status: Disabled

3.6.5 Measuring Dew Point

In this scenario, dew point can be measured without knowledge of the gas pressure. Connect the equipment as shown in
Figure 26 above, with or without a pressure sensor, and follow the normal operating procedures.
Optica™ Operator's Manual
Process Pressure (P
e
1
dew
1
Optional
Pressure
Sensor
Sensor
Figure 26: Measurement Scenario 1
) = 100 psi
1
e = Process Vapor Pressure
1
Tdew = Process Dew Point
1
Flowmeter
Chapter 3. Operation
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