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Kendali Digital
Pertemuan-2
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Introduction
Digital computer performs the control algorithm to controlthe
plant through A/D and D/A
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The digital deviceSoftware: the ailit! to read data from
input ports"
the ailit! to send data to output ports" internal data transfer
and mathematical operations" timer interrupt facilities for timing
the controller algorithm
#ardware:
Inputs $P% &memor!
'utputs
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Algorithm of control
•
(ead the desired value) (• (ead the plant output) *) from the
A/D converter
• $alculate the error signal) + , ( *
• $alculate the controller output) %
•
Send the controller output to D/A converter• .ait for the net
sampling instant
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S!stem 0odeling
• 0echanical s!stem
• +lectrical s!stem
• +lectromechanical s!stem
1or detail read chapter 2 ! !ourself
+ample:
1ind the transfer function of the s!stem
elow
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The sampling process
r3t4: analog signalr53t4: discrete signalP3t4: delta pulse train
3sampler4
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The D/A process
6ero-order hold 36'#4: Sin!al pengendali hasil olahan perang7at
digital diumpan7an
7emali 7e plant melalui DA$ dengan metode 8ero-order hod
36'#4
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6'#999
Impuls response of6'#
aplace transform of 6'#:
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Driving a plant ! a digital controller
Sampler gives information of the error signal
The digital controller process the error signal and then
producescontrol signals in discrete form9
The D/A converts the discrete control signals to its
analog form9
The analog form drives the plant to minimi8e the error
;uestion: #ow is the algorithm of the digital controller<
Tool of anal!sis: 6-transform
