DH Instruments ADCS-601, Operation And Maintenance Manual

Page: 157 / 174

7. MAINTENANCE OF TRACEABILITY AND RECALIBRATION
Page 145 © 2005 DH Instruments, Inc.
Install the CDGs on the two horizontal legs of the
KF40 cross so that they are in the same vertical
position as in their normal operating position. Use the
KF16 x KF40 adaptor provided with the ADCS-601
accessories to adapt the FPG8601’s CDG assembly
from KF16 to KF40.
Install a low vacuum reference on the top of the KF40
cross (a calibration ion gauge is recommended, not
included with the ADCS-601 system).
Press the [OK] button on the <Setup Verification> prompt. A second <Setup
Verification> prompt is presented.
Check all vacuum fittings as requested and press the [OK] button. The reference
roughing pump and turning pump will activate.
Observe the level of vacuum as indicated by the vacuum reference (ion gauge) and by the
rotation rate of the turbo pump displayed on the pump controller. When the vacuum is less
than 10 Pa, use the
[OPEN] buttons on the ADCS Tools Run Screen to open the CDG
isolation valves, opening the CDGs to the KF40 cross and the pumping system.
Allow the pump the pressure to pull down and stabilize.
Observe the level of vacuum as indicated by the vacuum reference.
Observe CDG readings on the ADCS Tools CDG Zero Run Screen . Using the
potentiometers on the top of the CDGs, adjust the CDGs to cause their output as indicated
on the
ADCS Tools CDG Zero Run Screen to agree with the value indicated by the vacuum
reference (ion gauge) .
Isolate the CDGs from the KF40 cross by pressing the [Close Valve] buttons on the ADCS
CDG Zero Run Screen .
Double check that the CDG isolation valves are CLOSED (exposing the CDGs to
atmospheric pressure will make it necessary to zero them again).
Bring the KF40 cross pressure back to atmospheric pressure by pressing the [STOP] button
(top sign) on the ADCS Main Tool Bar . Press [Yes] In response to the <Are you sure>
prompt if you are ready to end the CDG zeroing process. This causes the reference vacuum
pumps to turn OFF and vent.
Wait for the venting process to complete.
Remove the CDGs from the KF40 cross and return them to their normal operating position.
Reassemble the KF40 cross for normal ADCS-601 operation following steps through
above in reverse order.
Put the ADCS-601 in absolute measurement mode (see Section 4.2.3) and verify that the
vacuum reference pressure pulls down as expected.