Technical Description
Technical Handbook
019722-101 Rev. 05
19
SC-350/360
The micro controller automatically controls:
• lid open = stop,
• lid closed = start.
Keys
The keys on the control panel are controlled by the CPU board. All
debouncings are handled by the software.
Display
The display is a six multiplexed seven segment display unit of the
common anode type. The anodes are powered by Darlington
transistors T1-T6. The segments are powered by MOSFET transistors
T8-T15.
The green indicators LED1-LED3 above
Q
,
ACC
and
Start/Stop
are
powered by the other decimal point connections.
Each of the six display units is lit for about 270
μ
s, which gives a
cycle time of about 1.7 ms.
To avoid display flicker these are updated in the order DIS1, DIS3,
DIS4, DIS5, DIS2, DIS6.
Outputs
The extra port circuit is connected to the micro controller. This port
is updated between the time one display is switched off and the next
one is switched on. This is done by the micro controller IC3 sending
the port information on the P2 bus.
At the same time the negative clock signal (-CLK) goes low
immediately.
6.4 PSU Board and Transformer
Transformer
The primary winding of the transformer is supplied with either 110 V
AC or 230 V AC depending on the supply voltage used.
The secondary winding supplies 24 V DC. If the solenoid is activated
this voltage drops to about 20 V, with the open circuit voltage at this
point being about 30 V.
