VACUUBRAND PC 600 LAN NT - Manual (Page 59)

page 59 of 102
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
VNC 2 to a pressure < 0.5 Torr (mbar) (e.g. by
applying a good two-stage rotary vane pump).
➨
In ”Device menu”, select program ”Cal.Sens” at the controller.
+
The reading is automatically adjusted to ”zero”.
➨
Press the ”Enter” key to confirm.
0 mbar
Note: Adjustment under vacuum with an actual pressure higher than 0.5
Torr (mbar) reduces the accuracy of the measurement. If the pressure is
significantly higher than 0.5 Torr (mbar), adjustment to a reference pres-
sure is recommended.
Adjustment at a reference pressure
Instead of adjustment under vacuum to a pres-
sure < 0.5 Torr (mbar), adjustment to a precise-
ly known reference pressure within the range
of 0..... 15 Torr (20 mbar) is possible. Evacuate
the measurement connection of the VNC 2 to
a pressure within 0 ..... 15 Torr (0.....20 mbar).
➨
In ”Device menu”, select program ”Cal.Sens” at the controller.
+
The reading is automatically adjusted to ”zero”.
➨
Use the ▲ and ▼ keys to adjust the reading to the reference pressure
at the vacuum line within the range of 0 ..... 15 Torr (0.....20 mbar).
➨
Press the ”Enter” key 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).