Lamtec CMS, Manual

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5 Functional Description with Process Diagrams
5.4.4 Functional Description
Constant Control
The constant controller calculates a preset firing rate based on the actual value and the set-
point.
The unit of the setpoint corresponds to the unit of the actual value.
Control by Atmospheric Conditions
The firing rate controller controlled by atmospheric conditions determines its setpoint based
on the outdoor temperature. This must be assigned to an analogue temperature input.
See SAI configuration in chapter
4.6 SAI - Safe Analogue Input
The setpoint shift (setpoint pair and edge temperature) generates the setpoint. The firing rate
controller controlled by atmospheric conditions determines the firing rate default based on the
actual value and the generated setpoint.
Limiting the Firing Rate
If the parameters are set correctly, the presetting of the firing rate controller is limited by the
start-up circuit.
Burner Shut-off with Switching Thresholds:
Shut-off threshold:
If the firing rate controller detects that the boiler temperature or steam pressure exceeds a
configured threshold (switch-off threshold), it removes the signal ’burner ON’ in the CMS and
sets the logical signal ’burner OFF’.
Switch-on threshold:.
The signal ’burner ON’ is deactivated if the temperature falls below the switch-on threshold.
Base fire threshold:
If the base fire threshold is exceeded, the burner runs to base fire. In this case, it is switched
off after a certain time (soft stop time) if the actual value does not drop below the base fire
threshold.
5.5 SPS Parameters
The parameters between 1900 and 1999 are allocated to PLC. These parameters are freely
programmable by PLC programs. These are 16-bit parameters with full range of values. The
parameters can be edited in AL0.
At currently 50 of these PLC parameters are available. If required, it can be extended to up to
100 parameters.
P no. Description Attributes
56 Burner OFF threshold V1.0.0.0
Burner OFF (Difference to the setpoint) in °C or bar (xx.x).
Adjustment of the switch-off limit of the firing rate controller.
If the actual value exceeds the setpoint by the value entered in this parameter, the burner is
switched OFF.
The value entered is the difference between the current setpoint and the value at which the
burner is switched OFF. This value must be higher than the set upper limit of the control
range (P 55). Depending on the setting in P 61, the content is interpreted as °C (directly
without decimal point), as bar (resolution 0.1 bar, range 0.1 to 99.9 bar), or in digits.
Write: 0/GUI/UI
Read: 0
Default: 15
Min: 0
Max:999