Emerson Rosemount 370XA, System Reference Manual

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System Reference Manual 370XA Gas Chromatograph
7P00370-H01 APRIL 2014
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Figure 4-1. The timing of the valve switching to separate between two
components eluting from a column. The example on the left shows the ideal
time between the two peaks. The example on the right shows the valve timing
is too early, and will result in the exclusion of some of the normal-pentane.
Traditionally, highly trained gas chromatograph experts would
manually adjust the valve timing and tune the timing of the integration
events occasionally to account for the small changes in retention
times and measurement issues.
Auto valve timing (AVT) automates this process so that even an
inexperienced user can initiate an adjustment of the valve timing,
letting the GC’s internal algorithm adjust and optimize the valve timing
automatically.
To initiate AVT, go to the Control menu from the Local Operator
Interface or MON2020 and select Auto Valve Timing .
The AVT will use the calibration stream to make adjustments. The
configuration selection provides options for the starting point for the
adjustments:
• Use module default - The AVT algorithm will start using the
factory default values loaded into the module when the module
was originally built. Use this option when maintenance has
been performed on the module, for example, the analysis valve
diaphragms have been overhauled, and the retention times
have significantly changed from the last calibration.
• Use current - The AVT algorithm will start using the valve
timing and integration settings currently in the module.