Teledyne 4020 – Hydrocarbon analyzer (special version for automatic background gas switching) - Manual (Page 76)

Operation Model 4020
Teledyne Analytical Instruments 58
<Escape> Use Escape to move back to the Analyze Mode. Note that
the analyzer will now switch gas to the analyzer
depending on the choice shown on screen as detailed
below.
4.6.16.1 D ISABLED
When the valve selection mode “Disabled” is selected, the gas
connected to the sample port will be fed to the analyzer, i.e. the
“SAMPLE” port will always be open as the default stream fed to the
analyzer. During all modes of operation (Analyze, Span, or Zero), the
valve position will not be indicated on the screen as shown below.
or
and so forth for the zero mode.
4.6.16.2 U SER S ELECT
This option of valve selection allows the user to determine the
particular gas stream sent to the analyzer. Note that the valve selected
will be open during ALL modes of the instrument operation (Analyze,
Span and Zero).
There are three choices within the User Select option corresponding
to the valve the user elects to be open to the analyzer (Sample, Span or
Zero). The second line of the display will indicate the current valve
selection.
To select the valve to be opened to the analyzer:
<▲▼> From the VALVE SELECTIONS menu, Use the <▲▼>
keys to toggle the option to USER SELECT
Press to bring up the USER SELECT screen.