Allen-Bradley Logix5000 Reference Manual page 408

Chapter 9 Array (File)/Shift Instructions (BSL, BSR, FFL, FFU, LFL, LFU)
Condition
Rung-condition-in is true.
Examine .EN bit.
.EN Bit is set.
.LEN = 0
.LEN < 0
Shift array one position to the right.
Source
Array
bit
.DN bit is set.
.POS = .LEN
Postscan
408
Relay Ladder Action
.EN Bit = 1
.EN Bit = 0
Yes
No
Yes
.ER bit is set.
No
.UL Bit
The rung-condition-out is set to false.
Rockwell Automation Publication 1756-RM003N-EN-P - October 2011
.DN bit is set.
.Source Bit = 1
Examine source bit.
.Source Bit = 0
.UL bit is set.
Rung-condition-out is set
to true.
End
.UL bit remains set.