COFFEtek NEVA 4, Technical Manual

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COFFE tek LTD
11 22/02/08 Issue 1 NEVA 4
Circuit Description
25. The beverage machine is connected to a 230V single-phase supply that terminates at a
terminal block (TBA). From here AC supplies are taken to the heater element(s) and
Power Supply PCB.
26. A 15A fuse(s) protect the heater circuit(s). A solid state relay (SSR) and high temperature
cut-out are also placed in each heater circuit. The SSR switches the supply to the heater
as directed by the MPU Controller in response to data received from the temperature
sensor part of the temperature/level probe, thus maintaining the water in the boiler at the
correct temperature. However, if the water in the boiler starts to boil, the high
temperature cut-out removes the supply to the heater. Once operated, the cut-out must
be reset manually. The reset buttons are located on the boiler cover behind the
ingredient canisters. On the 3kW model the single active element is designated as
HEATER 1.
27. A 230V AC main supply is taken from the terminal block to the Power Supply PCB via the
On/Off switch. The Power Supply PCB provides DC supplies of 24V, 12V and 5V. The
24V DC output supplies the ingredient motors, whipper motors, extraction fan, SSR and
solenoid operated valves. The 12V DC output supplies the MPU Controller Board and
operational coin acceptor (if fitted).
28. The MPU Controller Board continually checks the status of input devices connected to
plugs J1 and J3, and responds to any change of state by signaling the operation of the
relevant output devices via on-board current drive transistors. Thus, for example, the
water level probe controls the operation of the inlet valve and the temperature sensor
controls the operation of the SSR.
29. The dispensing of a beverage begins with the keypad selection, which is scanned by the
MPU Controller Board via a ribbon connector. Control signals corresponding to the
required actions are then generated by the MPU Controller to operate the relevant output
devices in the correct sequence and for the specified duration. User data information is
then sent in parallel form to the front panel (LCD) display.