Agilent Technologies VS Series Operation Manual page 89

VS Series Helium Mass Spectrometer Leak Detectors
3.1.1.1 Split Flow Operation
Ground rules and assumptions:
The software limits split flow to no more than 1000 times (3 decades). If the split
❑
flow is turned ON and the leak rate entered is more than 1000 times higher than the
system leak rate, the system will not allow the split flow to turn ON and <> appears.
At the main screen, the system blinks the split flow symbol
❑
ON.
When split flow is turned ON, it displays the corrected leak rate but it knows the
❑
real leak rate value.
When ZERO is pressed with when split flow ON, the system zeroes out background
❑
up to a limit equal to the maximum split flow value.
To activate split flow:
1. Place the system into TEST mode and let the leak rate stabilize. Calibrate the system.
2. Press the Split Flow blue check button. The leak detector prompts you to enter the leak
rate for the customer's calibrated standard leak (what the leak rate should be).
The leak detector displays the corrected leak rate, essentially calculating a split flow
gain value. The leak detector automatically calculates the split flow factor, turns on and
calculates the range stop, based on the split flow factor.
When Split Flow is turned OFF, the system reverts back to the uncorrected leak rate.
This process must be repeated when reactivating split flow.
For Split Flow: Sniffer Mode (High Pressure Test) External Calibration: (E-6, E-5, E-4 std.
leaks only) AZ<0 Inactive:
1. Install the power/sniffing probe in the leak detector test port and press Test. Transfer
Point must be equal to or greater than 2 Torr but less than 10 Torr.
2. Use the power probe to adjust the test port pressure between 500mTorr and 1 Torr for
optimum response and cleanup performance.
3. Initiate a full internal calibration.
4. Go back in Test and Zero out the system background.
5. Install the power probe in the outlet of the standard leak and allow for system
stabilization.
6. Activate the Split Flow option and input the value of the calibrated leak and press OK.
7. Remove the probe from the calibrated leak and verify that the that the leak detector
cleans up.
when split flow is
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