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8 Options
Parameter 0050 and 0051 are necessary only in case a setpoint changeover is required.
8.1.5 Setpoint Changeover
You can switch setpoint via input at terminal 5. When you use a version with fixed setpoint val-
ue you are able to select through this contact one of two values listed in parameters P0048
and P0050 with this contact.
While control by atmospheric conditions is activated additionally you are able to select be-
tween two pairs of limit values (see control by atmospheric conditions and limit ranges). Pa-
rameters for setpoint 1 (for setpoint switching) and setpoint min 1 (for control by atmospheric
conditions) are the same. Similarly, parameters setpoint 2 and setpoint min 2. The corre-
sponding content is assigned accordingly to selected configuration.
While ’control by atmospheric conditions’ is activated and parameters are set correspondingly
you may also implement an external setpoint default. This means setpoint values can be ad-
justed via potentiometer (or switched through resistors) manually or automatically. By con-
necting a change-over switch, you can implement a night-time reduction instead of ’control by
atmospheric conditions’. A ’control by atmospheric conditions’ in combination with night-time
reduction is also possible. In order to achieve this combine the control by atmospheric condi-
tions with setpoint switch over.
8.1.6 Start-up Sequence
The firing rate controller has a start-up cycle in order to slow down burners’ firing rate while
starting. The start-up cycle is passed during each new burner start. The internal firing rate is
held at user-adjusted value (P 0044) as long as the boiler is cold. The actual value is below
parameter set limit (P 0043. If controllers’ actual value is larger/equal to the parameter set
start-up maximum temperature, this startup cycle is cancelled.
In order to prevent that too large power demand of the plant having the consequence that boil-
er temperature for ending start-up cycle is not reached, in parallel a startup timer is also trig-
gered in parallel (timer adjustable by operator, P0045). As internal firing rate reaches
parameter set start-up firing rate, output is increased linearly step-by-step up to maximum
firing rate. The rise of this linear increase is calculated from parameter set start-up time.
When the start-up circuit is active, the icon is displayed in the UI300.
0052 0; in the usage of 0 ... 20 mA at the setpoint input
0052 40; in the usage of 4 ... 20 mA at the setpoint input
0053 200
0048 Setpoint 1 which should be set with 0/4 mA at setpoint input
0049 Setpoint 1 which should be set with 20 mA at setpoint input
0050 Setpoint 2 which should be set with 0/4 mA at setpoint input
0051 Setpoint 2 which should be set with 20 mA at setpoint input
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