It is not clear to me. Is the 8-bit byte ("file") the total size of the buffer or is that the payload that needs to be shifted. There are SHIFT instructions to handle buffer of WORD or DWORD sizes.

The SHRB instruction might be useful to you when the buffer is bigger than a standard size. Have a look at documentation about this instruction.

dareng_68

Thanks for the swift response, I am trying to manage a reject system which is 8 movements down the line from detection. 8 bits is the requirement (00000000) although it does not matter if a single byte is used, where if there is a reject detected this will go into bit 1 (00000001) each movement will shift left and if the fourth is also detected as a reject this will be (00001001)  if the eighth bit is monitored and comes through as a  (10010000) this will enable the reject point.

Hope this makes sense.

The problem is easy enough. Use the shift word left instruction. Each time the instruction receives a clock pulse the bits will be shifted. Use the in-software documentation to read up on the instruction.

I do recommend that you use a WORD instead of the BYTE. The quickest is to use a memory address like say MW20. The entry point will be M21.0 (!!) and the exit point is either the 8th bit (M21.7) or 9th bit (M20.0) depending of the timing of the logics.

Then you have the choice of coding in LAD, STL, SCL or FBD. STL documentation has the most description and is added as an attachment.

use static variable (DB or M or STAT in FB)

Reset: simply set variable to zero (for example when line is unloaded)

Queue:

On movement trigger (move FIFO by one position and declare reject when bit 8 = 1)

A #Trigger  // trigger is pulse
JCN SKIP

L #FIFO   // FIFO bit register
SLW 1     // Shift by one position
T #FIFO  // Store
AW 128       // 128 = bit 8 set all other clear
L 0
A(
<>I
)
S #Reject_Demand

SKIP: A #New_Reject // New Reject pulse enters new reject demand to FIFO
JCN PROK

L #FIFO   // FIFO bit register
OW 1     // Set Bit 0
T #FIFO  // Store

PROK: NOP 0

// Reject Demand must be cleared when executed.