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english
On commissioning the water level in the boiler, the system waits for the level probe to be covered before
activating the ON/OFF relay.
The sensitivity of the level probes can be varied using a parameter in the TECHNICAl lEVEl Programming,
in the following cases:
-> lOW sensitivity
150kΩ
for example in the presence of a water softener
-> MEDIUM sensitivity
400KΩ
normal water
-> HIGH sensitivity
1MΩ
for example in the event of mountain water or glass level
indicator
7.3 Coffee boiler heating
WITH ON/OFF ADjUSTMENT WITH HySTERESIS OF 2°C
The temperature is adjusted with a hysteresis of 2°C. The heating element is controlled by the ON/OFF relay,
which is de-energised on reaching the programmed temperature T°SET (see TECHNICAl lEVEl Program-
ming) and it re-energises when it drops by 2°C. To avoid vibrations on the trigger threshold, a time-controlled
filter is also fitted.
To activate this function, you will need to set in TECHNICAl PROGRAMMING all the pid constants to 0 (see
relevant paragraph).
WITH PID ADjUSTMENT (DEFAUlT SETTING)
The temperature is adjusted according to a proportional, integrated and derivative algorithm.
(see TECHNICAl lEVEl Programming for parameter settings)
The heating control is enabled when the dosage function is IDlE-ON and it uses a temperature probe and a
low voltage command RISCAF for triac or solid state relay with PID function.
T°SET
PID
The temperature is adjusted according to an algorithm which uses 3 constants:
- proportional
(kp)
- integrated
(ki)
- derivative
(kd)
The three constants must be adapted to all types of coffee doses according to the power characteris-
tics of the heating element, the size of the boiler, its dissipation, and so on.
The "setpoint value or T°SET" is defined as the temperature the boiler needs to be at to operate normally
- If during the heating or maintenance phase the temperature oscillates excessively around the T°SET, with
peak values which do not attenuate over time, the proportional constant needs to be lowered: Kp
- If during the maintenance phase the temperature oscillates excessively around the T°SET, with a pro-
longed oscillation time and peak values which do not attenuate over time, the integrated constant needs
to be lowered: Ki
- If during the heating or maintenance phase the temperature oscillates excessively and is often more than
the T°SET, but it attenuates over time, the derivative constant needs to be lowered: Kd
- If during the heating phase the temperature tends to be below the value of the T°SET, differing from it more
and more, the derivative constant needs to be increased: Kd
- If during the heating phase the temperature tends to be below the value of the T°SET constantly, the
proportional constant needs to be increased: Kp and the integrated constant also needs to be increased
slightly: Ki
- If during the maintenance phase the temperature tends to be below or above the value of the T°SET con-
stantly, the integrated constant needs to be increased: Ki and the proportional constant also needs to be
increased slightly: Kp
