68 Advanced User Guide
5 Detectors
How FID units are displayed in Agilent data systems and on the GC
The GC displays the FID signal in picoamperes (pA). The
following table lists how different data systems convert the
display units to reporting units.
To light the FID flame
Press [Front Det] or [Back Det], scroll to Flame, then press
[On/Yes].
To extinguish the FID flame
Press [Front Det] or [Back Det], scroll to Flame, then press
[Off/No].
FID automatic reignition (Lit offset)
Lit offset is the expected minimum difference between the FID
output with the flame lit and the output with the flame off. The
GC checks this value during runs and when loading a method.
During a run, if the output falls below the Lit offset value, the FID
will attempt to reignite three times. If after the third attempt
the output does not increase by at least this value, the detector
shuts down all functions except temperature and makeup gas
flow.
When loading a method that includes a Flame On setting, the GC
performs a similar check. If the detector output is less than the
Lit offset, it will attempt reignition after reaching method
setpoints.
Table 11 Unit conversions
Data system Height units LSV (height units) Area units Noise (ASTM)
*
Agilent data system 1 pA 1.3 x10
-4
pA 1 pA-sec 0.038 pA
SIGRange
†
0 1 x 10
-4
pA 1.3 x 10
-4
pA 1 x 10
-4
pA 0.038 pA
SIGRange 5 3.2 x 10
-3
pA 4.2 x 10
-3
pA 3.2 x 10
-3
pA 0.038 pA
Analog 1V
‡
1.25 x 10
-4
pA device dependent 1.25 x 10
-4
pA 0.038 pA
* Noise is recommended maximum when determining MDL.
† SIGRange used with 3393 and 3396 integrators.
‡ Analog 1V is an approximate value.
To Next Page
Loading...
Need help?
General
