D
=
4
∗
KD
∗
T
and
4
∗
KD = D/T
Assuming a sampling period of T=1ms, the parameters of the digital filter are:
KP = 20.6
KD
=
68.6
The DMC-14XX can be programmed with the instruction:
KP
20.6
KD
68.6
In a similar manner, other filters can be programmed. The procedure is simplified by the following
table, which summarizes the relationship between the various filters.
Equivalent Filter Form
DMC-14XX
Digital
D(z) =K((z-A)/z) + Cz/(z-1)
Digital
D(z) = 4 KP + 4 KD(1-z-1) + KI/2(1-z-1)
KP, KD, KI,
K = (KP + KD)
⋅
4
A
=
KD/(KP+KD)
C = KI/2
Continuous G(s)
=
(P + Ds + I/s)
PID, T
P = 4 KP
D
=
4
T*KD
I = KI/2T
DMC-14x5/6
Chapter 10 Theory of Operation
i
149
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