Allen-Bradley Logix5000 Reference Manual page 414

Chapter 9 Array (File)/Shift Instructions (BSL, BSR, FFL, FFU, LFL, LFU)
Condition
Rung-condition-in is true.
.EN = 0
Examine .EN bit.
.EN = 1
Yes
.LEN < 0
No
Yes
.POS < 0
No
.EM bit is cleared.
.DN is cleared.
Yes
.POS = 0
No
Yes
≥
.POS .LEN
No
Postscan
414
Relay Ladder Action
.EN bit is set.
.EM bit is set.
.DN is set.
.EM bit is set.
.DN bit is set.
The rung-condition-out is set to false.
Rockwell Automation Publication 1756-RM003N-EN-P - October 2011
Yes
.LEN < 0
No
Yes
.POS < 0
No
.EM bit is cleared.
.DN is cleared.
.POS = .POS + 1
Yes
≥
.POS .LEN .DN bit is set.
No
.POS or
Yes
Major Fault
.LEN > Size Of
Array
No
Yes
.POS > .LEN .POS = .POS - 1
No
FIFO[.POS - 1] = Source
Rung-condition-out is set
to true.
End
.EM bit is set.
.DN is set.