Ladder Logic Programming Instructions


The following is a growing list of ladder logic programming instruction definitions and video examples.

Each instruction is hyper-linked to a brief description as well as a video example. The intent is to supplement the help files already provided with RSLogix 5000 programming and configuration software. While the help files do a good job of defining the instructions, seeing is believing.

The following definitions and examples are specific to Allen Bradley’s RSLogix 5000 software; however the concepts detailed here can be applied across multiple software applications.

ABS                         Absolute Value
ADD                        Add Instruction
AFI                         Always False Instruction
AND                        Bitwise And Instruction
ACS                         Arc Cosine
ASN                        Arc Sine
ATN                        Arc Tangent
AVE                        Average Instruction
BRK                         Break (See FOR as well)
BSL                          Bit Shift Left
BSR                          Bit Shift Right
BTD                         Bit Field Distribute
CLR                         Clear Instruction
CMP                        Compare Instruction
COP                         Copy Instruction
COS                         Cosine
CPS                         Copy Synchronous
CPT                         Compute
CTD                         Count down
CTU                         Count up
DEG                         Radians To Degrees
DIV                         Divide
EQU                        Equal To
EVENT                  Trigger Event Task
FAL                        File Arithmetic Logical
FFL                         FIFO Load
FFU                        FIFO Unload
FLL                         Fill File
FOR                        For Routine Instruction (See BRK as well)
FRD                        From BCD
FSC                         File Search & Compare
GEQ                       Greater Than Or Equal To
GRT                       Greater Than
GSV                       Get System Value
IOT                         Immediate Output
JMP                       Jump To Label (See LBL as well)
JSR, SBR, RET    Jump To Subroutine, Subroutine, Return From Subroutine
JXR                        Jump To External Routine
LBL                         Label (See JMP as well)
LEQ                        Less Than Or Equal To
LES                         Less Than
LFL                         LIFO Load
LFU                        LIFO Unload
LIM                        Limit Test
LN                          Natural Log
LOG                       Log Base 10
MCR                      Master Control Reset
MEQ                      Mask Equal
MOD                     Modulo
MOV                     Move
MSG                      Message
MUL                      Multiply
MVM                    Mask Move
NEG                       Negate
NEQ                       Not Equal To
NOP                       No Operation
NOT                       Bitwise NOT
ONS                       Oneshot
OR                          Bitwise Inclusive OR
OSF                        One Shot Falling
OSR                        One Shot Rising
OTE                        Output Energize
OTL                        Output Latch
OTU                       Output Unlatch
RAD                       Degrees To Radians
RES                         Reset
RET                        Return From Subroutine
RTO                        Retentive Timer
SBR                        Subroutine
SIN                         Sine
SIZE                       Size array
SQI                         Sequencer Input
SQL                        Sequencer Load
SQO                       Sequencer Output
SQR                       Square Root
SRT                        Sort File
SSV                        Set System Value
STD                        Standard Deviation
SUB                        Subtract
SWPB                    Swap Byte
TAN                       Tangent
TND                       Temporary End
TOD                       To BCD
TOF                        Timer Off Delay
TON                       Timer On Delay
TRN                        Truncate
UID                        User Interrupt Disable
UIE                         User Interrupt Enable
XIC                         Examine If Closed
XIO                         Examine If Open
XOR                       Bitwise Exclusive OR
XPY                        X To Power Of Y