VACUUBRAND CVC 2II - Manual (Page 31)

page 31 of 36
Documents are only to be used and distributed completely and unchanged. It is strictly the users´ responsibility to check
carefully the validity of this document with respect to his product. manual-no.: 997835 / 15/12/2009
The device was adjusted using factory standards, which are traceable through regular
calibration in an accredited laboratory (German Calibration service) to the national stand-
ard. Depending on the process and/or accuracy requirements, check the adjustment
and readjust if necessary. For readjustment, the device has to be adjusted both at
atmospheric pressure as well as under vacuum.
The adjustment mode can be activated only if the process control is inactive. Press
key STOP if necessary.
Readjustment
Adjustment at atmospheric pressure
Ventilate the controller and/or the vacuum system. Make sure
that the vacuum connection at the controller is at atmospheric
pressure.
➨ Press key p▲ or p▼ simultaneous with key MODE, the con-
troller then switches to the adjustment mode.
☞ ”CAL” is displayed for approx. 2 seconds.
➨ While ”CAL” is displayed, press key START/STOP.
➨ Use key p▲ or p▼ to adjust the reading to actual atmos-
pheric pressure.
➨ Press key STOP to confirm.
Note: To determine the actual atmospheric pressure, use an accurate barometer or get accurate reading
from the weather service, the next airport.......(take into account the difference in altitude between e. g.
airport and laboratory).
Adjustment under vacuum
Evacuate the controller to a pressure < 0.5 mbar (e. g. by apply-
ing a good rotary vane pump).
➨ Press key p▲ or p▼ simultaneous with key MODE, the con-
troller then switches to the adjustment mode.
☞ ”CAL” is displayed for approx. 2 seconds.
➨ While ”CAL” is displayed, press key START/STOP.
☞ The reading is automatically adjusted to ”zero”.
➨ Press key STOP to confirm.
Note: Adjustment under vacuum with an actual pressure higher than 0.5 mbar reduces the accuracy of the
measurement. If the pressure is significantly higher than 0.5 mbar, adjustment to a reference pressure is
recommended.
Adjustment at a reference pressure
Instead of adjustment under vacuum to a pressure < 0.5 mbar,
adjustment to a reference pressure within the range of 0 ..... 20
mbar is possible.
➨ Press key p▲ or p▼ simultaneous with key MODE, the con-
troller then switches to the adjustment mode.
☞ ”CAL” is displayed for approx. 2 seconds.
➨ While ”CAL” is displayed, press key START/STOP.
☞ The reading is automatically adjusted to ”zero”.
➨ Use keys p▲ or p▼ to adjust the display to the reference
pressure at the vacuum line within the range of 0 ..... 20
mbar.
➨ Press key STOP to confirm.
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 state, failure of valves or the diaphragm).
p
0 .... 20 mbar
p
+ CAL MODE
p
+ CAL MODE
p
+ CAL MODE