Lamtec VMS 4, Manual

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5 Firing Rate Controller (optional)
5.1.3 Control by Atmospheric Condition
If the burner firing rate controller is configured as "controlled by atmospheric conditions" the
setpoint value can be shifted between the parameterised setpoint minimum and setpoint max-
imum by connecting another PT 100 temperature sensor. When utilising control by atmos-
pheric conditions, the outside temperature is a component of setpoint calculation. This allows
the operator to enter a minimum and a maximum setpoint, between which the outside temper-
ature can determine the final setpoint value.
Fig. 5-1 Control by atmospheric conditions
5.1.4 Setpoint Changeover
You can switch the setpoint with the input "setpoint switchover". If you use a version with fixed
setpoint value it is possible to select one of the two values, which are entered in the parame-
ters 796 and 798 with this contact.
If you have activated the control by atmospheric conditions additionally, you can select be-
tween two pairs of limit values (see control by atmospheric conditions and limit ranges). The
parameters for setpoint 1 (for setpoint switching) and setpoint min. 1 (for control by atmos-
pheric conditions) are equal. Likewise the parameters setpoint 2 and setpoint min. 2. The cor-
responding content is assigned according to the configuration.
When activating the "control by atmospheric conditions” option and setting the adjustable pa-
rameters, you may realise an external setpoint default. In other words, the setpoint can be ad-
justed manually or automatically via a potentiometer (or switched through resistors). By
connecting a change-over switch, you can implement a night-time reduction instead of control
by atmospheric conditions. A control by atmospheric conditions and a night-time reduction can
be realised simultaneously, if you combine the control by atmospheric conditions with the set-
point switching.