Siemens RWF55.5 User Manual page 63

2 procedures
Conditions

Building Technologies Division
Infrastructure & Cities Sector
The tUnE function uses 2 different methods that are automatically selected depending
on the dynamic state of the actual value and the deviation from the setpoint at startup.
tUnE can be started from within any dynamic actual value sequence.
If there is a great difference between actual value and setpoint when tUnE is
activated, a switching line is established about which the controlled variable performs
forced oscillations during the self-setting process. The switching line is set to such a
level that the actual value should not exceed the setpoint.
X
Figure 31: Great difference between actual value and setpoint
With a small deviation between setpoint and actual value (after the controlled system
has settled, for instance), forced oscillation about the setpoint is performed.
X
Figure 32: Small control deviation
The data of the controlled system recorded for the forced oscillations are used to
calculate the controller parameters rt, dt, Pb1 and a filter time constant
value filtering that is optimized for this controlled system.
- High-fire operation in modulating burner mode
- The thermostat function (relay K1) must be constantly activated; otherwise tUnE will
be canceled and no optimized controller parameters will be adopted
- The above mentioned actual value oscillations during the self-setting process must
not exceed the upper threshold of the thermostat function (increase if necessary, and
lower the setpoint)
Note!
A successfully started Self-setting function is automatically aborted after 2 hours.
This could occur in the case of a controlled system that responds slowly, for example,
where, even after 2 hours, the described procedures cannot be successfully
completed.
User Manual RWF55...
9 Self-setting function
Switching
level
7866d18e/1011
7866d19/0911
dF1
for actual
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CC1U7867en
05.11.2013