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

Page 51

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Appendix A

AĆ10

2.

Determine the nominal block-transfer time.

3.

Compute the approximate scanner time for each block-transfer
channel.

4.

Compute the encoder re-/write-block-transfer time.

Example Computation

An example computation to determine the block-transfer timing with a
PLC-3 family processor follows. The example is based on these facts:

user program contains 20K words

channel 1 contains five I/O chassis with a total of seven block-transfer

modules including one encoder module

channel 2 contains two I/O chassis with no block-transfer modules

channel 3 contains two I/O chassis with one encoder module

channel 4 is made inactive through processor LIST

1.

Diagram the chassis connected in series to each channel (up to four)
of your scanner module. Then, fill in the information called for
below. Example values have been added.

1

2

3

4

1

1

1

1

2

0

2

0

0

Make inactive through processor LIST

= I/O chassis

n = number of block-transfer

modules in chassis

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