D - application notes, Appendix, Unsigned integer to string conversion – Rockwell Automation 2706-DXX Dataliner Message Display DL5 Series User Manual

Page 109

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2706-UM001A-US-P

Appendix

D

Application Notes

Unsigned Integer to String
Conversion

Serial protocol uses decimal values in the range of 0 to 65535 to send
variable data (Ctrl-V command). PLCs that do not support unsigned
integers can only generate values in the range of -32768 to 32767. To send
decimal values in the range used by the serial protocol, use the following
ladder logic. This program converts a 16-bit signed integer to an unsigned
ASCII decimal string. The ASCII decimal string can then be used to
generate serial commands for the DL5.

In this example, the 16-bit integer is in N17:0 (signed value = -12264,
unsigned value = 53272). The conversion uses N17:1 and ST18:1-4 as
temporary buffers. The ASCII decimal string is returned in ST18:5. The
conversion routine ladder logic is as follows:

AIC

Integer to String
Source N17:0

-12264<

Dest

ST18:5

GEQ

Grtr Than or Eql (A>=B)
Source A

-12264<

Source B

0

N17:0

0<

0000

AIC

Integer to String
Source

6
6<

Dest

ST18:1

LES

Less Than or Eql (A<B)
Source A

-12264<

Source B

0

N17:0

0<

0001

SUB

Subtract
Source A

N17:0

-12264<

Source B

-5536

15536<

Dest

N17:1

3272<

AIC

Integer to String
Source

5
5<

Dest

ST18:1

LES

Less Than or Eql (A<B)
Source A

-12264<

Source B

-5536

N17:0

-5536<

0002

SUB

Subtract
Source A

N17:0

-12264<

Source B

-15536

-15536<

Dest

N17:1

3272<

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