Rockwell Automation 1769-SM1 Compact I/O to DPI/SCANport Module User Manual

Page 54

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4-6

Understanding the I/O Image

Regardless of the Datalink combination, x1 will always contain the LSW
and x2 will always contain the MSW. In the following examples,
parameter 242 - [Power Up Marker] in a PowerFlex 70 drive contains a
value of 88.4541 hours.

The following example shows an unlike Datalink pair of A2 and B1.
With A1 already assigned, the next two available Datalinks were used.

32-bit data is stored in binary as follows:

Example: Parameter 242 - [Power Up Marker] = 88.4541 hours

MSW = 13

decimal

= 1101

binary

= 2

19

+ 2

18

+ 2

16

= 851968

LSW = 32573

decimal

851968 + 32573 = 884541

Datalink

Most/Least Significant Word

Parameter Data (decimal)

A1

LSW

242

32573

A2

- Not Used -

0

0

A1

- Not Used -

0

0

A2

MSW

242

13

A1

LSW

242

32573

A2

MSW

242

13

Datalink

Most/Least Significant Word

Parameter Data (decimal)

A2

MSW

242

13

B1

LSW

242

32573

MSW

2

31

through 2

16

LSW

2

15

through 2

0

Most Significant Word Value

Least Significant Word Value

0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 1

0 1 1 1 1 1 1 1 0 0 1 1 1 1 0 1

Bit

31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

851968

32573

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