Yokogawa GC8000 Process Gas Chromatograph - Manual (Page 111)

<1. Overview>
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IM 11B08A01-01E
Auto-operation
setting
Yes/No
No initial value
1st auto-start
time
Until the heater is turned on.
Range: 0 to 50000 s
Initial value: 0
The purpose is to prevent deterioration of the column by turning the oven heater on while the
column is not suffi ciently substituted by the carrier gas.
Set a time (s) when the carrier gas stream within the column system is suffi ciently substituted by
carrier gas. The rough indication is the time (s) obtained by dividing about 5 times the volume
(ml) of the column total inner volume by the carrier gas DET fl ow rate (ml/s).
2nd auto-start
time
Until the detector is turned on.
Range: 0 to 50000 s
Initial value: 0 s
TCD detector:
The purpose is to prevent fi lament from burning out as a result of turning on the air in the TCD
without being suffi ciently substituted by carrier gas.
Set 600 s (10 min) or more.
FID detector:
Even if the heater is at ON status after a lapse of the 1st auto-start time, when the detector is
turned on while the temperature within the isothermal oven is low, the vent may be clogged as
a result of condensation or freezing (0°C or lower) of moisture generated by combustion of FID
detector. To prevent this, set the required time.
The rough indication is a time (s) when SV value of isothermal oven temperature exceeds 20°C
and reaches PV value.
FID-MC:
The purpose is the same as the FID detection, and in addition to that, to prevent catalyst
deterioration by turning the detector on while the air inside the MC (methane converter) is not
suffi ciently substituted by carrier gas.
Set the time (s) in which SV value of the isothermal oven temperature exceeds 20°C and
reaches PV value, or 600 s (10 min), whichever is longer.
3rd auto-start
time
Time until Run mode command is executed
Range: 0 to 50000 s
Initial value: 0 s
TCD detector:
Even if the detector is turned on after a lapse of the 2nd auto-start time, the baseline drifts until
the current value becomes stable. If such drifting becomes signifi cant, an accurate analysis
cannot be performed. To prevent this, set the required time.
The rough indicator for the setting to start up the analyzer at room temperature is 12 hours or
more in total of the 2nd and the 3rd auto-start time.
Example: The 2nd auto-start time: 600 s (10 minutes)
The 3rd auto-start time: 43200 s (12 hours)
FID detector:
Set at least “140 s” for generating detector anti-infl ammation alarm as a result of decrease in
pressure of utility gas, etc.
The rough indication for confi guring the analyzer to star up at room temperature is:
When the isothermal oven temperature is set to 145°C or lower:
2 to 4 hours in total of the 2nd and the 3rd auto-start time.
Example: The 2nd auto-start time: 3600 s (1 hour)
The 3rd auto-start time: 7200 s (2 hours)
When the isothermal oven temperature is set to 146°C or higher:
4 to 8 hours in total of the 2nd and the 3rd auto-start time.
Example: The 2nd auto-start time: 3600 s (1 hour)
The 3rd auto-start time: 18000 s (5 hours)
FID-MC:
Set at least “140 s” or more than the time required for generating detector anti-infl ammation
alarm as a result of decrease in pressure of utility gas, etc.
In addition, there is a case when accurate analysis cannot be performed until the catalyst within
the MC becomes activate, even if the detector is turned on after a lapse of the 2nd auto-start
time. To prevent this, set the required time.
The rough indicator for the setting to start up the analyzer at room temperature is 4 to 8 hours in
total of the 2nd and the 3rd auto-start time.
Example: The 2nd auto-start time: 3600 s (1 hour)
The 3rd auto-start time: 18000 s (5 hours)
2nd Edition : May 11, 2012-00