Chapter 3 Functional descriptions
SMSO-2-02.03- 15.07.03 59
3.2.19 Unit control system (EHS)
The unit control system is the coffee machine’s “brain” and it
controls all the machine functions It contains the programs,
monitors all the sensors and controls the consumers via the
power PCB. The most important elements of the unit control
system are the microprocessor, the memory chip that contains
the program (Flash ROM) and a special memory chip
(EEPROM) for all the system meters. The RAM containing all
the parameters has a backup power battery so that if the ma-
chine is disconnected from the mains, its settings are not
deleted. The RAM data can be saved on the “SAVE DATA”
card as a backup for the settings.
Function
The unit control system processes the signals from the various
sensors in line with the program configuration and the vari-
able settings, and thus controls the consumers. Thus all the
sensors are wired directly to this PCB. You will find informa-
tion relating to the control system in the functional description
of each component. You will find the basic information about
the program in the programming instructions
The illustration of the unit control system below clearly shows
the many sensor connections.
µ
DANGER TO LIFE / MATERIAL DAMAGE
When carrying out any work on electrical
appliances, fatal injuries may be caused by
electric shock, if live parts are touched.
Even at low voltages, contact with live parts
can also cause bodily harm to people, Such
work must be carried out only by authorised
and qualified electricians.
The battery on the unit control system could dis-
charge, if the strip conductor side (i.e. the under-
neath of the power PCBs) is touched by conducting
surfaces. Therefore always place the unit control
system on a non-conducting mat (ESD mat) etc.
The unit control system will only function perfectly if
the PE conductor is correctly connected. Therefore
when changing the unit control system please make
sure that the PE conductor is perfectly connected to
the power PCB.
Static discharge caused while working on the PCBs
can destroy them. When handling PCBs make sure
that they cannot suffer electro-static discharge and
always store susceptible components in anti-static
packaging.
Replacing the Flash-ROM and the EEPROM modules:
Make sure that the connection prongs are standing
up in a straight row, and that that the notches on the
housing match the ones in the base. (for details on
replacing: see section on “Maintenance”)
Flash ROM and EEPROM components: The connection
prongs must be straight and the notches on the IC housing
and the base must correspond
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