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Functional limitations
Output level monitoring is not active in the following cases:
•
Proportional band Xp = 0
E
•
Autotuning active
•
Manual mode
•
Ramp function active
•
Controller operating as program controller
Parameter dimensioning
Appropriate dimensioning of parameters used for determining the mean output level is required for the output level
monitoring to function correctly.
The controller differential band around the actual value defines the corrected state. It should be di mensioned so that
it is adhered to during normal operation. The progression of the actual value can, for example, be recorded with the
startup function of the setup program. Determination of the mean output level starts when the actual value enters the
control differential band. Calculation of the mean output lev el starts over if there is temporary deviation from the con-
trol differential band during output level deter mination or if the setpoint value is changed by more than 0.5 × control
differential band Dx.
A mean output level is calculated via the determination time using a moving average. The time chosen should be
long enough to ensure as accurate a calculation as possible. The determination time is fol lowed by a waiting period
of 0.5 x reset time Tn, during which it is checked whether the actual value and output level move within the specified
limits. If one of the limits is exceeded, the calculation restarts. After successful calculation, the output level monitoring
is active.
x
y
T
C
Dy
x
w
y
y
A
Actual value
Output level
Determination time
Output level band
Product:
Temperature controller XT-T1
T
0.5 x Tn
C
w
Setpoint value
y
Average output level
A
rt
Reset time
Dx
Controller differential band
Revision 2.0 – Issue September 2018
Dx
t
Dy
t
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