Varian 990 dCLD II, Operation Manual

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Model 990 dCLD II Component Leak Detector
5-22
8. Turn the leak off to isolate the calibrated leak in the system.
9. Wait for the system leak rate to decrease to a stable value. Type ZERO<CR> and check
that the SPEC TUBE LED on the front of the control unit flashes while zeroing is in
process. The zeroing process runs for only a few seconds (less than five).
10. When zeroing is complete, turn the leak on to expose the calibrated leak to the foreline
of the turbo pump again. Wait for the system to stabilize.
11. Type CALIBRATE<CR> and check that the SPEC TUBE LED flashes on the front of the
control unit while calibration is in process.
12. When calibration is complete, verify that the leak rate matches the value listed on the
tag of the calibrated leak in the vacuum system using the ?LEAK<CR> command.
13. Isolate the calibrated leak and, using ?LEAK<CR>, observe that the leak rate decreases
to near zero.
14. If the time for the leak rate decay is more than a few seconds, there could be a vacuum
leak or the vacuum system might not be fully stabilized. It might be necessary to invoke
the ZERO function (step 9) again to re-zero the 990 dCLD II.
5.6.2 Manual Tuning via the Optional Front Control Panel
1. Operate the valves in the vacuum system to rough pump, then expose the calibrated
leak to the foreline of the spectrometer assembly high vacuum pump.
2. Wait approximately 20 seconds for the leak to stabilize.
3. Move to the Manual Tuning Screen (Section 4.7.2 “Manual Tuning” on page 4-19).
4. Change the ION V parameter value up or down to find the peak signal and press OK .
5. Change the VAR FOCUS parameter value up or down to find the peak signal and
press OK .
6. Change the REPELLER parameter value up or down to find the peak signal and press OK .