VACUUBRAND PC 620 - Manual (Page 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.: 999029 / 01/10/2009
page 36 of 48
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▼ simultaneously with key MODE, the
controller then switches to the adjustment mode.
☞ CAL is displayed for approx. 2 seconds.
➨ While CAL is displayed, press key START/STOP.
➨ Use keys p▲ and p▼ to adjust the reading to actual atmos-
pheric pressure.
➨ Press key START/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▼ simultaneously with key MODE, the
controller 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 START/STOP to confirm.
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▼ simultaneously with key MODE, the
controller 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▲ and p▼ to adjust the display to the reference
pressure at the vacuum line within the range of 0 ..... 20
mbar.
➨ Press key START/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
The vacuum gauge was adjusted using factory standards, which are traceable through
regular calibration in an accredited laboratory (German Calibration service) to the na-
tional standard. 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.
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.