MKS HPS 903 Series, Руководство по эксплуатации и обслуживанию

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13 Cold Cathode Ionization Vacuum Sensor
Cold cathode ionization systems are gas dependent and the Series 903
(IMT's) output is defined for air/nitrogen. Refer to page 16, Using the Series
903 (IMT) with Other Gases, to determine the true pressure of another gas.
Equation for Converting Voltage to Pressure
The following equation converts the (IMT) voltage reading V to a pressure reading
P when using air or nitrogen. The voltage must be within the domain of the
equation or an incorrect pressure reading will result.
Where,
P is in Torr, mbar, microns, or Pascal (depending on K)
V is in volts for 1.5 < V < 8.7
K = 11.000 for Torr, 10.875 for mbar,
8.000 for microns, 8.875 for Pascal.
Using the Set Point
Attach a digital voltmeter to the
Common tip jack and the Set Point tip jack
on the (IMT) as shown below. Adjust the potentiometer with a small
screwdriver until the voltage reading coincides with the desired set point
pressure. This pressure is shown on the graph on the previous page or is
calculated from the equation above.
When the set point LED is on, the measured pressure is below the set
point value, the normally open relay contact is closed, and the normally
closed contact is open. When the LED is off, the measured pressure is
above the set point value, the normally open relay contact is open, and the
normally closed contact is closed. If a power failure occurs, the set point
and its LED will turn off.
Set Point
Potentiometer
Tip Jacks
Set Point LED
P = 10 ( V-K )