Introduction
Sometimes it is necessary to byte shift data right by one byte to insert a new byte at the head of a buffer. This could be for strings or data. However the current PLC shift instructions don't enable this function easily as data is often byte swapped in a word.
The attached sample CX-Programmer file includes a Function Block (FB) which allows users to shift a 'buffer' of data by one byte. The FB also inserts a new byte at the head of the buffer.
Example
Data in 'buffer' before shift.
| 1122 | 3344 | 5566 | 7788 |
Data in 'buffer' after shift (assuming that new byte to insert at head is 0x99)
| 9911 | 2233 | 4455 | 6677 | 88 |
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Note: The Function Block is written for CJ1/CS1 V4.x CPU's or CJ2 V1.x |
