Output regulator (optional)
Method of operation
Parameterised startup time
Startup circuit
Specified load
Sp
ec
if e
d
ad
i
lo
Time
max. load/
or highest
programmed
point
Specified load
Parameterised
startup load
Set-point switch-over
The set-point can be switched over via a digital input. In versions with a
fixed set-point, this contact can be used to select between the two values
entered in the parameters list.
If, in addition, weather control is activated, a selection is made between
two pairs of limiting values (see Weather control and Limiting ranges). The
parameters for Set-point 1 (for set-point switch-over) and Set-point min. 1
(for weather control) are equal. Similarly for the parameters Set-point 2 and
Set-point min. 2. The relevant content is assigned in accordance with the
configuration.
Activating the "Weather control” option and adjusting the variable
parameters can also be used to implement external set-point specification.
In other words, the set-point can be altered manually or automatically via a
potentiometer (or switched through resistors). Thus, by connecting a
double-throw switch, night-time reduction could be implemented instead
of weather control. Night-time reduction and weather control can be
achieved simultaneously by combining the weather controller with the set-
point switch-over. When the weather controller is active, the compound's
feedback can no longer proceed completely redundantly.
Startup circuit
The load regulator has a startup circuit, in order to brake the burner's start
load. The startup circuit is run during each new burner start. The internal
load is held at a value adjustable by the user, for as long as the boiler is
cold (actual value is below a user-adjustable limit). If the regulator's actual
value is equal to or larger than the parameterised startup maximum
temperature, this limit is overridden.
In order to prevent a situation where with an excessively large demand on
system output, the boiler temperature necessary to override the startup
circuit is not reached, a startup timer is also triggered in parallel (this timer
can also be adjusted by the operator). Once the internal load's value
reaches the parameterised startup load, the output limit is increased
linearly step-wise up to the maximum load. The slope of this linear increase
is calculated from the parameterised startup time.
33
Countdown until
the internal load
reaches the
specified load
Normal
operation
Ignition
procedure
Basic load
Ignition
