4 Technical description
4.1 Dispenser board
All the electronic devices including power transformer, except of the main switch with indicator
lamp, are located on a printed board. The dimensions of the board are approximately 215 x
234 mm. Figure 11 shows the board with all the connectors and terminals.
The description is divided into power supply, motordriver, controller and firmware.
4.1.1 Power supply
The power supply unit generates the two regulated vo12 V/1A and + 5 V/1 A for the
logic, as well as an unregulated DC voltage of approx. 40 V/3.5 A for the steppermotor. The
stabilization is done by linear voltage regulators.
4.1.2 Motordriver
The driver board consists of 2 H-bridge circuits to drive the two motor phases. The phase cur-
rent is 4 A while running, and 2 A when stopped. To control the current, a chopper circuit with
20 kHz chopper-frequency is used.
Dependent on the dispensing speed the processor generates a fullstep- or a halfsteppattern.
For speeds faster than 10 m/min, the motor is driven by a fullstep- pattern.
In the case of overheating, short-circuit or malfunction the motordriver is switched off and the
red LED
FAULT
is illuminated. In this case the labeler must be switched off and on again.
4.1.3 Controller
The single chip micro-controller H8/532 with external 32 K-Byte EPROM controls the functions
of the labelling process.
All outputs are buffered by photo-couplers.
All the inputs are pulled up to +12V with 2.2 K and are equipped with a low-pass filter.
The A/D-converter scans periodically the value of the settings of the 3 potentiometers
(R101....R103).
The control current of the label scanner is generated by a controlled current source.
5999.515-01E 12.06.2007 WM
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