Siemens Synco 700 - Page 74

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Building Technologies Modular Heating Controller RMH760B CE1P3133en
HVAC Products 6 Boiler temperature control 05.02.2007
b
50
48
52
°C
44
46
t
t
reset
TBo
TBoSetpt
3132D09
TBuOffPt
TBuOnPt
b Reset integral TBo Actual value of the boiler temperature
TBoSetpt Boiler temperature setpoint t
Time
TBuOffPt Burner’s switch-off temperature t
reset
Time to reset
TBuOnPt Burner’s switch-on temperature
Through the generation of the temperature-time integral it is not only the period of time
that is considered, but also the extent of overshoot. This means that when the over-
shoot is significant, burner stage 2 will be locked earlier.
When the reset integral (area "b" in the diagram) reaches the set value of the reset
integral of stage 2 (point in time t
reset
), stage 2 will be locked and the basic stage switched
off.
1
0
INT
max.
RlsBuSt2
1
0
BuSt2
t
RlsINT
3133D15
0
1
0
t
t
t
t
BuSt1
max.
TBoSrtpt +
1
/
2
SDBo
TBo
RstINT
TBoSetpt -
1
/
2
SDBo
RstINT
BuSt1 Burner stage 1 SD
Switching differential
BuSt2 Burner stage 2 Setpt Setpoint
INT
Integral
t
Time
RlsBuSt2
Release of burner stage 2
TBo Boiler temperature
Rst Reset
If, with stages 1 and 2 released, both stages are locked at the same time, the basic
stage will be switched off with a delay of 10 seconds. Switching off in 2 stages also
reduces the pressure shocks in the gas supply line. This prevents unnecessary lockout
in the case of large boiler outputs.
Note