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Siemens Building Technologies Basic Documentation LMV5... CC1P7550en
HVAC Products 6 Temperature or pressure controller (internal load controller LC) 13.08.2004
6.8 Cold start thermal shock protection (CSTP)
Thermal shock protection can be activated and deactivated.
A differentiation is made between modulating and multistage control.
The cold start sequence is activated when, on startup, the actual value lies below the
ON threshold).
If thermal shock protection is activated, the manipulated variable on cold start will be
increased in a stepwise fashion using the set load step (or the next stage will be acti-
vated).
The output will be increased as soon as the actual value has exceeded the start value
of the load stage by the setpoint step.
If this switching threshold is not reached within the adjustable maximum time, heating
will automatically be ensured by the next output stage. When the OFF threshold is
reached, the cold start sequence will be terminated in order to switch to normal control
operation.
Parameters: Thermal shock protection on / off ColdStartOn
Activation value for thermal shock protection ThresholdOn
Deactivation value for thermal shock protection ThresholdOff
Load step (only for modulating mode) StageLoad
Setpoint step, modulating StageStep_Mod
Setpoint step, multistage StageStep_Stage
Max. time, modulating per step MaxTmeMod
Max. time, multistage per step MaxTmeStage
6.8.1 CSTP – modulating operation
For the output step, any output value in % can be predefined.
100 % divided by the output step gives the number of possible stages.
Spacing of temperature lines
corresponds to the setpoint steps
Manipulated
variable
Actual value
Setpoint
Threshold OFF
Threshold ON
Output
steps
7550d04E/0202
Setpoint step is reached
before max. time has elapsed.
Manipulated variable increased
by output step
Burner off,
actual value
below thresh-
old ON.
Burner will be
switched on
Setpoint step not reached,
but max. time exceeded.
Therefore, manipulated
variable increased by
output step
⇒
Actual value reached.
Threshold OFF
Change to control
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