Allen-Bradley Logix5000 Reference Manual page 432

Chapter 9 Array (File)/Shift Instructions (BSL, BSR, FFL, FFU, LFL, LFU)
Condition
Rung-condition-in is true.
.EU = 0
Examine .EU bit.
.EU = 1
Yes
.LEN < 0
No
Yes
.POS < 0
No
.EM bit is cleared
.DN is cleared
Yes
.EM bit is set.
.POS = 0
No
Yes
≥
.DN bit is set.
.POS .LEN
No
Postscan
432
Relay Ladder Action
.EU bit is set.
.EM bit is cleared.
.DN is cleared.
.EM bit is set.
.POS
.POS = .POS -1
Destination = LIFO[control.POS]
LIFO[control.POS) = 0
Rung-condition-out is set
to true.
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
Yes
≤
.EM bit is set.
.POS 1
No
Yes
Destination = 0
.POS < 1
No
Yes
> .
LEN
.POS = .LEN
No
Yes
.LEN > Size Of
Major Fault
Array
No
End
.EM bit is set.
.DN is set.