Equivalent filter form – Galil DMC-2X00 User Manual

Page 200

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The function G is equivalent to a digital filter of the form:

D(z) = 4KP + 4KD(1-z-1)

where

P

=

4

∗ KP

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-2x00 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-2x00

Digital

D(z)

=[K(z-A/z) + Cz/(z-1)]

∗ (1-B)/(Z-B)

Digital

D(z) = [4 KP + 4 KD(1-z-1) + KI/2(1-z-1)]

∗(1-B)/(Z-B)

KP, KD, KI, PL K = (KP + KD)

4

A

=

KD/(KP+KD)

C = KI/2

B = PL

Continuous G(s)

=

(P + Ds + I/s)

∗ a/S+a

PID, T

P = 4 KP

D

=

4

T*KD

I = KI/2T

a = 1/T ln (1/PL)

190

Chapter 10 Theory of Operation

DMC-2X00

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