Rockwell Automation 1771-DE Absolute Encoder Module User Manual User Manual

Page 47

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Appendix A

AĆ6

Figure A.2

PLCĆ2/30 Local System Example

PLC–2/30

1
7
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L

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E

Rack 1

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L

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E

Rack 3

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E

Rack 4

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E

Rack 2

10813-I

Solution:

Program length = 4K words
Number of chassis = 4 (1 assigned rack number per chassis)
Number of block-transfer words, W = 2 (read) or 20 (write)

1.

Calculate the system values.

Processor Scan Time (PS) = (5 ms/1K words) x (4K words) = 20

ms