DETEKTORELEKTRONIK
CONTROL ELECTRONICS
The boards of the control electronics are of double-
height Eurocard format. They are plugged next to
one another in the electronics rack. Sequence from
left to right: interface board 3, PCPU-2, detector
amplifier, options, power supply.
All electronic boards are maintenance-free. In the
event of faults, please contact our service techni-
cians.
Interface board 3
Interface module 3 is the link between the PCPU-2
controller and the terminal board or the heaters of the
chromatograph. The functions:
Analog-to-digital converter with multiplexer in
bridge circuit for 8 temperatures measured using
Pt100
Optional analog-to-digital converter with multi-
plexer for voltages: 2 temperatures measured using
thermocouple
Processing of mains interrupt for temperature con-
trol
Digital outputs control the electronic heater swit-
ches
Control of the terminal board with digital outputs,
digital inputs and analog outputs.
Pilot lamps for temperature controller
The lamps indicate how the heaters are operating. The
AC heater voltages are switched at the passage through
zero. The heating power results from the time between
two 20 ms pulses. The lamps 1 to 10 are assigned to the
temperature controllers 1 to 10.
Pilot lamps ready/not ready
The green lamp indicates that the chromatograph is
ready, the yellow lamp signals not ready. Refer to Reg-
ister 5: Status to find out how the statuses are defined
and how they can be influenced.
Plugs X3 and X4
All signals for the digital outputs, digital inputs and
analog outputs from and to the terminal board are via
plug X3 .
Plug X4 connects the interface board 3 to the heater
control board for the temperature controllers: tempera-
ture measurements, mains interrupt and control signals
for the heaters.
Conversion of analog outputs
The four analog outputs can be converted from
0 to 20 mA to 4 to 20 mA. The table shows the plug
assignments.
Analog output Plug
1
2
3
4
X6
X5
X8
X7
Jumpers inserted: 4 to 20 mA, jumpers open: 0 to 20 mA
Maximum load: 750
Ω
X4 X3
9
1
3
5
7
10
2
4
6
8
X6
X4
X5
X8
X7
X3
X5 ... X8
4 ... 20 mA
0 ... 20 mA
Control electronics
10
9STEUER.CHP, Stand 20.05.94
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