function Innovation & Technology AS
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Manual – KNX MultiLight Art.nr 44001
Doc.no. D-TS-ML-K-005-A
6.6
PI Regulator
The KNX MultiLight thermostat can control heating and cooling systems with Pulse-With-
Modulation. The communication object for the PWM control value output is a 1.byte 0-
100% of the type DPT5.001. The control value will automatically be transmitted every 40.
minutes and can also be transmitted when the value has changed a specific percentage,
see Figure 13.
Figure 13 - Heating PI-regulator
The PI-regulator is configured with a proportional factor (K
p
) and a reset time (T
i
). The
equation for the regulator output is shown in (3).
The integration of the error for each regulator evaluation is substituted by the step
number (30 second increments) multiplied with the last error function: e(n)∙n divided by
the time constant, see equation (3)
The proportional factor K
p
:
range
al
proportion
K
P
_
1
(1)
The error function e(n):
e(n) = set_point - actual_temperature (2)
The regulator output equation:
I
P
I
P
T
n
n
e
K
T
n
n
e
n
e
K
n
u
2
1
)
(
2
)
(
)
(
)
(
(3)