Siemens PGC 302 Edition II - Attenuation

Ionization detectors
Range Detector current 0(4) to 20 mA in attenuation
0
0
1
2
3
4
5
6
7
8
0 to 0.80 pA
0 to 13 nA
0 to 26 nA
0 to 52 nA
0 to 0.104
µ
A
0 to 0.208
µ
A
0 to 0.416
µ
A
0 to 0.832
µ
A
0 to 1.664
µ
A
0 to 3.328
µ
A
0
14
15
16
17
18
19
20
21
22
TCD
Range Detector voltage 0(4) to 20 mA in attenuation
0
0
1
2
3
4
0 to 30.5
µ
V
0 to 31.25 mV
0 to 62.5 mV
0 to 125 mV
0 to 250 mV
0 to 500 mV
0
10
11
12
13
14
Attenuation
The attenuation is the factor by which the detector sig-
nal is to be reduced (attenuated) for the recorder output.
This is represented as a two’s exponent 2
0
to 2
22
.
Select the function Signals in the selection display and
move the cursor for the desired channel to the line Re-
corder/Attenuation. Enter the desired value using the
numeric keypad and confirm using .
Relationship between
recorder signal and detector signal
The attenuation always refers to the direct detector sig-
nal independent of the range setting. The signal ampli-
tude at the recorder output does not change when the
range is switched over because the chromatograph
takes into account the range during the digital signal
processing. However, since the ranges are not cali-
brated with respect to one another, the signal may
nevertheless differ by up to 10 %.
The tables on the left list the relationship between the
detector and recorder signals for the various detectors.
Digital increments
It is not meaningful to combine a large range with a
small attenuation. Digital steps become visible on the
recorder if the attenuation is too small. If the attenua-
tion is too large, large peaks already reach the internal
full-scale value before the recorder full-scale value has
been reached.
Largest attenuation
The attenuation should never be selected to be
larger than that which corresponds to the full-scale
value in the respective range.
Smallest attenuation
The attenuation should always be selected larger
than the value for the range.
Example
Range 4 with FID requires a minimum attenuation
of 5 and a maximum attenuation of 18.
RETURN
Chromatogram on the recorder
5SCHREIB.CHP, Stand Dezember 22, 1999
9