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7.7 Three-step control
The flow temperature can be controlled using a PI algorithm. The valve reacts to pulses that the
controller emits when a system deviation occurs. The length of the first pulse, in particular, de
-
pends on the extent of the system deviation and the selected
Proportional gain K
P
(the pulse
length increases as K
P
increases). The pulse and pause lengths change continuously until the
system deviation has been eliminated. The pause length between the single pulses is greatly in
-
fluenced by the
Reset time T
N
(the pause length increases as T
N
increases).
The
Transit time T
Y
specifies the time required by the valve to travel through the range of 0 to
100 %.
The three-step control can be configured separately for individual heating circuits, for the DHW
heating and for the pre-control circuit.
Functions
WE Configuration
Three-step control
for heating circuit
ON
0.5
200 s
120 s
240 s
Co1, 2, 3 -> Fb15 = ON
K
P
(proportional gain) / 0.1 to 50.0
T
N
(reset time) / 1 to 999 s
T
Y
(transit time) / 15, 30, …, 240 s
UP lag time / 120 to 1200 s
Three-step control
for DHW heating
ON
0.5
200 s
120 s
Co4 -> Fb09 = ON
K
P
(proportional gain) / 0.1 to 50.0
T
N
(reset time) / 1 to 999 s
T
Y
(transit time) / 15, 30, …, 120 s
Three-step control
for pre-control circuit
ON
0.5
200 s
120 s
Co5 -> Fb14 = ON
K
P
(proportional gain) / 0.1 to 50.0
T
N
(reset time) / 1 to 999 s
T
Y
(transit time) / 15, 30, …, 240 s
No further pulses are issued at the three-step outputs when the control signal deactivation func
-
tion is activated when the total of the timing pulses (uninterrupted in one direction) is larger than
three times the control valve transit time T
Y
. In this case, it can be assumed that the control valve
is either completely open or completely closed; other signals do not cause any changes in the
control valve.
Function
WE Configuration
Control signal deactivation OFF Co5 -> Fb18 = ON
62 EB 5179 EN
System-wide functions