SAS ST-550 zPID, Руководство пользователя

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ST-550 zPID
21
Temperature control
This parameter determines the frequency of water temperature measurement (control) behind the CH
or DHW valve. If the sensor indicates a change in temperature (deviation from the set value), then the
electric valve will open or close by the set stroke, in order to return to the pre-set temperature.
Opening time
This parameter defines the time needed for the valve actuator to open the valve from 0% to 100%
position. This value should be adjusted to the value given on the actuator rating plate.
Single stroke
This function is used to define the maximum single stroke (opening or closing) that the valve may make
during one temperature sampling.
Minimum opening
This function is used to set the minimum value of valve opening. The valve does not close any further.
Valve type
This option is used to select the type of valve used.
For the function of weather control to be active, the external sensor mustn't be exposed to sunlight or
influenced by the weather conditions.
After it is installed in an appropriate place, weather-based control function needs to be activated in the
controller menu.
For the valve to operate correctly, the user defines the pre-set temperature (behind the valve)
for 4 intermediate external temperatures:
TEMP FOR -20ºC
TEMP FOR -10ºC
TEMP FOR 0ºC
TEMP FOR 10ºC
Heating curve – it is a curve according to which
the pre-set controller temperature is determined,
on the basis of external temperature. In our
controller, this curve is constructed on the basis
of four pre-set temperatures for respective values
of external temperatures.
The more points constructing the curve, the
greater its accuracy, which allows its flexible
shaping. In our opinion, four points seem a very
good compromise ensuring decent accuracy and
easiness of setting the course of this curve.
In our controller:
X
A
= -20ºC, X
C
= 0ºC,
X
B
= -10ºC, X
D
= 10ºC,
Y
A
, Y
B
, Y
C
, Y
D
– pre-set temperatures of the valve for respective external temperatures: X
A
, X
B
, X
C
, X
D
After weather-based control function has been activated, pre-set valve temperature function is no
longer available.
Return protection
This function enables the user to set CH boiler protection against too cool water returning from the
main circulation, which could cause low-temperature CH boiler corrosion. The return protection involves
closing the valve when the temperature is too low, until the short circulation of the boiler reaches the
appropriate temperature. This function also protects the CH boiler against too high temperature by
preventing the returning water from boiling.
After activating it, the user pre-sets the minimum and the maximum acceptable return.