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7.8 On/off control
The flow temperature can be controlled by an on/off signal. The controlled valve is opened
when the flow temperature falls below the set point by T = 0.5 x
Hysteresis
. When the flow tem
-
perature exceeds the set point by T = 0.5 x
Hysteresis
, the control valve is closed. The greater the
Hysteresis
selected, the lower the switching frequency. The
UP lag time
parameter indicates the
time span which the circulation pump continues to run after the control valve is closed (the pa
-
rameter only needs to be set for the heating circuits HK1, HK2 and HK3).
By entering
Minimum activation time,
a burner once switched on remains switched on for the
time entered, regardless of how the temperature develops. Likewise, a burner that has been
switched off due to the temperatures remains switched off for the time entered in
Minimum de
-
activation time
.
The on/off control can be configured separately for the individual heating circuits and for the
pre-control circuit.
Functions
WE Configuration
Three-step control
for heating circuit
ON
5 °C
120 s
120 s
240 s
Co1, 2, 3 -> Fb15 = OFF
Hysteresis / 1 to 30 °C
Minimum activation time / 0 to 600 s
Minimum deactivation time / 0 to 600 s
UP lag time / 120 to 1200 s
Three-step control
for pre-control circuit
ON
5 °C
120 s
120 s
Co5 -> Fb14 = OFF
Hysteresis / 1 to 30 °C
Minimum activation time / 0 to 600 s
Minimum deactivation time / 0 to 600 s
7.9 Continuous-action control
The flow temperature can be controlled using a PID algorithm. The valve receives an analog 0 to
10 V signal issued by the controller. The proportional-action component causes an immediate
change in the 0 to 10 V signal when a system deviation arises (the larger the
K
P
, the greater the
change). The integral-action component first affects the control after a certain time:
T
N
stands
for the time that passes until the I-action component has changed the output signal so far as the
P-action component just did (the larger the
T
N
, the slower the rate in change). The D-action com
-
ponent causes every change in system deviation to have any increased effect on the output sig
-
nal (the larger the
T
V
, the more intensified the change).
The continuous-action control can be configured separately for individual heating circuits, for
the DHW heating and for the pre-control circuit.
EB 5179 EN 63
System-wide functions