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13 Detector
13.2 Hydrogen flame ionization detector (FID)
Select the optimum value in accordance with the peak half width. (Refer to “13.4 Filter
Signal Time Constant”.)
SIGNAL OUTPUT PORT
Selection: Off/Ch1/Ch2/Ch3/Ch4, Default: (Channel is automatically assigned.)
Select the digital and analog signals output channels. Four channels are available.
However, for analog output, only Ch1 and Ch2 are available as standard.
BACKGROUND SIG. SAVE
Selection: Off/Buff 1/Buff 2, Default: Off
Background baseline signals can be saved for the purpose of background subtraction.
BACKGROUND SIG COMP.
Selection: Off/Buff 1/Buff 2, Default: Off
Subtracts the saved background signal baseline from the actual baseline. This produces
a stable baseline despite considerable baseline fluctuations
DET SIG SUBTRACTION
Selection: Off/DET# 1/DET# 2/DET# 3/DET# 4, Default: Off
Subtracts the detector signal of one detector from the signal of another detector. This
function is mainly used in a dual column flow line to subtract the data acquired without
an injection from the data acquired with an injection. The background signal is eliminated.
For the details on “SIGNAL OUTPUT PORT”, “BACKGROUND SIG. SAVE”, “BACKGROUND
SIG COMP.” and “DET SIG SUBTRACTION”, refer to “13.5 Setting the Output Signals”.
SIGNAL RANGE
Selection: ×1/×10-1/×10-2/×10-3/×10-4, Default: /×10-1
Multiplies the analog signal by the coefficient “10-x” for a linear analog signal type.
If the data processing unit is saturated, for example, change the setting from “×1” to
“×10-1”, from “×10-2” to “×10-3”. In case of the digital signal, the signal is always output
with “×1”.
SIGNAL ATTENUATION
Selection: ×1/×2-1/×2-2/×2-3/×2-4, Default: /×2-1
Multiplies the analog signal by the coefficient “2-x” for a wide analog signal type.
If the data processing unit is saturated, for example, change the setting from “×1” to “×2-1”,
from “×2-2” to “×2-3”. In case of the digital signal, the signal is always output with “×1”.
ANALOG SIGNAL TYPE
Selection: Linear/Wide, Default: Linear
Set this item when the GC is connected to a Chromatopac in analog format.
When the GC is connected to a C-R8A, the value set here does not affect the signal
because they are connected by a digital RS-232C cable.
Wide ... Select wide when connecting the GC to the C-R7A/CR-7A plus.
The signal, multiplied by 1/2, is output from the GC; then, the signal received by
the Chromatopac is multiplied by 2.
When connecting the GC to a C-R7A/CR-7A plus for the first time, or replacing
the Chromatopac, set the detector signal output to “Off” and perform
calibration. (For the calibration procedure, refer to “2.7 Connecting external
device cables”.)
Linear ... Select linear when connecting the GC to any Chromatopac other than the CR8A/C-R7A/CR-7A plus.
When connecting the GC to a C-R7A/CR-7A plus and setting the “ANALOG
SIGNAL TYPE” to “Linear”, the optional signal cable (linear, P/N 221-4725192) is required.
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GC-2010