Siemens RWF 50.2, Инструкции по установке, использованию и обслуживанию

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5.6 Cold start of plant

Note!
Functions
Cold start of plant
and
Thermal shock protection (TSS)
are interlocked.
Only one function can be activated, but never both at the same time.
When a heating system is switched off for a longer period of time, the actual value will
drop of course.
To achieve a faster control response, the controller immediately starts in high-fire
operation as soon as the control deviation (x-w) drops below a certain limit value.
This limit is calculated as follows:
Limit value = 2 x (
HYS1
-
HYS3
)
In that case, the response threshold (q) is inactive, independent of operating mode and
controlled variable (temperature or pressure).
Operating mode: Modulating, 3-position output
HYS1
= -5 K
HYS3
= +5 K
w = 60 °C
Limit value = 2 x (-5-5) = 2 x (-10) = -20 K
At an actual value below 40 °C, heating up immediately starts in low-fire operation, and
not in thermostat mode.
7866d10(0911
HYS3
HYS1
2
x (-)
H
YS1
HY
S3
db
Figure 14: Control sequence
Cold start of plant
Interlocking
Heating controller
Example
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