VACUUBRAND PC 620 NT plastic housing - Manual (Page 70)

page 70 of 113
Adjustment under vacuum
An adjustment under vacuum is only possible
if the pressure is lower than 15 Torr (20 mbar)
absolute.
Evacuate the measurement connection of the
CVC 3000 to a pressure < 0.1 Torr (mbar)
(e.g. by applying a good two-stage rotary vane
pump).
➨
In ”Configuration” menu, select program ”Adjustment” at the controller.
+
The reading is automatically adjusted to ”zero”.
➨
Press the selection knob to confirm.
0 mbar
Note: Adjustment under vacuum with an actual pressure higher than 0.1
Torr (mbar) reduces the accuracy of the measurement. If the pressure is
significantly higher than 0.1 Torr (mbar), adjustment to a reference pres-
sure is recommended.
Adjustment at a reference pressure
Instead of adjustment under vacuum to a pres-
sure < 0.1 Torr (mbar), adjustment to a pre-
cisely known reference pressure within the
range of 0..... 15 Torr (20 mbar) is possible.
Evacuate the measurement connection of the
CVC 3000 to a pressure within 0 ..... 15 Torr
(0.....20 mbar).
➨
In ”Configuration” menu, select program ”Adjustment” at the controller.
+
The reading is automatically adjusted to ”zero”.
➨
Use the selection knob to adjust the display to the reference pressure
at the vacuum line within the range of 0 ..... 15 Torr (0.....20 mbar).
➨
Press the selection knob to confirm.
0...20 mbar
Note: The accuracy of the value of the reference pressure will directly
affect the accuracy of the adjustment. If the nominal ultimate vacuum
of a diaphragm pump is used as reference vacuum, the accuracy of the
controller might be doubtful. The diaphragm pump may not achieve the
specified value (due to condensate, poor condition, failure of valves or
diaphragm, leaks).