DETECTOR ELECTRONICS
There is a separate double-height Eurocard for
each type of detector. The module contains all
power supplies, amplifiers and compensating cir-
cuits where required. Two modules are inserted for
channels A and B in the electronics frame on the
right of the PCPU-2.
All electronic modules are maintenance-free. In the
event of faults, please contact our service techni-
cians.
Signal flow
The detector signal is applied on the detector module to
a precision analog-to-digital converter with a resolution
of 20 bits. This corresponds to a dynamic range of 10
6
.
The converter can be operated in up to 9 ranges depend-
ing on the type of detector. The ranges result in an atte-
nuation of 2
0
to 2
8
.
The detector modules have their own microcontroller.
This receives its parameters from the controller
(PCPU-2) via the bus board and delivers its results to
the controller.
The controller uses these digitized measured values for
peak recognition and evaluation. At the same time, it
converts them into an analog recorder signal of
0 to 20 mA. Further details, on e.g. the relationship be-
tween detector input signal and recorder signal, can be
found in Register 5: Chromatogram on the recorder.
Compensation
The detector boards have no control elements. The
microcontroller on the detector board carries out the
zero adjustment. To find out how this is carried out,
refer to Register 5: Detectors: Adjustment of zero.
Setting of channel A or B
The jumpers X201 and X202 on the detector boards
select whether a detector is channel A or B.
X8
X201
X202
Detector A
X 202
X 201
Detector B
X 202
X 201
Detector electronics
4
9DETEKT.CHP, Stand Dezember 22, 1999
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