Ladder Diagram Safety Instructions

Routines in the safety task can use the following types of ladder diagram safety instructions.

When instructions that result in values with decimal place are used with REAL or LREAL operands, Rockwell Automation has verified the precision to 6 decimal places.

Advanced Process

Mnemonic	Name	Description	Logix Designer Application
FGEN	Function Generator	Converts an input based on a piece-wise linear function.	Version 38 or later

Advanced Math

Rockwell Automation has not done independent mathematical analysis of the numerical algorithms used in any of the following advanced math instructions. If you require a specific degree of accuracy, you must functionally test this instruction over your expected input domain.

Mnemonic	Name	Description	Logix Designer Application
EXPT	X to the Power of Y	Returns the value of X to the power of Y.	Version 36 or later
XPY	X to the Power of Y	Returns the value of X to the power of Y.	Version 35 or earlier
LG	Natural Log	Compute the natural log of a number.	All versions
LOG	Log Base 10	Compute the log base 10 of a number.	All versions

Array (File)

Mnemonic	Name	Description	Logix Designer Application
AVE	File Average	Calculate the mean/average over a set of values.	All versions
COP	Copy File	Copy binary data from one tag to another (no type conversion). When you use the COP instruction in a safety routine, you must verify that the length is a constant and that the source and destination length are the same.	All versions
FAL	File Arithmetic and Logic	Perform copy, arithmetic, logic, and function operations on data that is stored in an array.	All versions
FLL	File Fill	Fill the elements of an array with the source value, while leaving the source value unchanged.	All versions
FSC	File Search and Compare	Compare the values in an array, element by element.	All versions
SIZE	Size in Elements	Find the size of a dimension of an array.	All versions
STD	File Standard Deviation	Calculate the standard deviation over a set of values.	All versions
BSL	Bit Shift Left	Shifts the specified number of bits to the left.	All versions
BSU	Bit Shift Right	Shifts the specified number of bits to the right.	All versions
FFL	Fifo Load	Store a value into an array by using first-in/first-out semantics.	All versions
FFU	Fifo Unload	Retrieve a value from an array by using last-in/first-out semantics.	All versions
LFL	Lifo Load	Store a value into an array by using last-in/first-out semantics.	All versions
LFU	Lifo Unload	Retrieve a value from an array by using last-in/first-out semantics.	All versions

Bit

Mnemonic	Name	Description	Logix Designer Application
ONS	One Shot	Allows an event to occur one time.	All versions
OSR	One Shot Falling	Sets an output bit for one scan on the true-to-false (falling) edge of rung state.	All versions
OSF	One Shot Rising	Sets an output bit for one scan on the false-to-true (rising) edge of rung state.	All versions
OTE	Output Energize	Controls a bit (it performs both Set and Clear operations based on rung state).	All versions
OTL	Output Latch	Set a bit (retentive).	All versions
OOTUTL	Output Unlatch	Clear bit (retentive).	All versions
XIC	Examine if Closed	Examines the data bit to set or clear the rung condition.	All versions
XIO	Examine if Open	Examines the data bit to set or clear the rung condition.	All versions

Time/Counter

Mnemonic	Name	Description	Logix Designer Application
CTD	Count Down	Count down.	All versions
CTU	Count Up	Count up.	All versions
RES	Reset	Reset a timer or counter.	All versions
RTO	Retentive Timer On	Accumulate time.	All versions
TOF	Off-delay Timer	Time how long a timer is disabled.	All versions
TON	On-delay Timer	Time how long a timer is enabled.	All versions

Compare

Mnemonic	Name	Description	Logix Designer Application
EQ	Equal To	Test whether two values are equal.	Version 36 or later
EQU	Equal To	Test whether two values are equal.	Version 35 or earlier
CMP	Compare	Perform a comparison on the arithmetic operations that you specify in the expression.	All versions
GE	Greater Than Or Equal To	Test whether one value is greater than or equal to a second value.	Version 36 or later
GEQ	Greater Than Or Equal To	Test whether one value is greater than or equal to a second value.	Version 35 or earlier
GT	Greater Than	Test whether one value is greater than a second value.	Version 36 or later
GRT	Greater Than	Test whether one value is greater than a second value.	Version 35 or earlier
IsINF	If Infinity	Check if floating point value is +/- infinity.	All versions
IsNAN	Is Not a Number	Check if floating point value is Not-a-Number.	All versions
LE	Less Than or Equal To	Test whether one value is less than or equal to a second value.	Version 36 or later
LEQ	Less Than or Equal To	Test whether one value is less than or equal to a second value.	Version 35 or earlier
LT	Less Than	Test whether one value is less than a second value.	Version 36 or later
LES	Less Than	Test whether one value is less than a second value.	Version 35 or earlier
LIMIT	Limit	Test whether a value falls within a specified range.	Version 36 or later
LIM	Limit	Test whether a value falls within a specified range.	Version 35 or earlier
MEQ	Mask Equal To	Pass source and compare values through a mask and test whether they are equal.	All versions
NE	Not Equal	Test whether one value is not equal to a second value.	Version 36 or later
NEQ	Not Equal	Test whether one value is not equal to a second value.	Version 35 or earlier

Move/Logical

Mnemonic	Name	Description	Logix Designer Application
AND	Bitwise AND	Perform bitwise AND operation.	All versions
CLR	Clear	Clear a value.	All versions
MOVE	Move	Copy a value.	Version 36 or later
MOV	Move	Copy a value.	Version 35 or earlier
MVM	Masked Move	Copy a specific part of an integer.	All versions
NOT	Bitwise Not	Perform bitwise NOT operation.	All versions
OR	Bitwise Or	Perform bitwise OR operation.	All versions
SWPB	Swap Byte	Rearrange the bytes of a value.	All versions
XOR	Bitwise Exclusive Or	Perform bitwise exclusive OR operation.	All versions

Program Control

Mnemonic	Name	Description	Logix Designer Application
AFI	Always False Instruction	Forces a rung to false (rung continues to execute).	All versions
EVENT	Trigger Event Task	Triggers one execution of an event task. The event instruction triggers a scan of the standard task.	All versions
JMP	Jump To Label	Scan of logic jumps to a labeled location within the same routine.	All versions
JSR	Jump to Subroutine	Jump to a separate routine.	All versions
LBL	Label	Identifies a target location for a JMP instruction.	All versions
MCR	Master Control Reset	Forces every rung in a section of logic to execute in the False state.	All versions
NOP	No Operation	Insert a placeholder in the logic.	All versions
RET	Return	Return the results of a subroutine.	All versions
SBR	Subroutine	Accept data that is passed to a subroutine by the JSR instruction.	All versions
TND	Temporary End	Mark a temporary end that halts routine execution.	All versions

Compute/Math

Rockwell Automation has done no independent mathematical analysis of the numerical algorithms used in the SQRT or SQR instructions. If you require a specific degree of accuracy, you must functionally test this instruction over your expected input domain.

Mnemonic	Name	Description	Logix Designer Application
ABS	Absolute Value	Take the absolute value of a value.	All versions
ADD	Add	Add two values.	All versions
CPT	Compute	Perform the arithmetic operation that is defined in the expression.	All versions
DIV	Divide	Divide two values.	All versions
MOD	Modulo	Determine the remainder after one value is divided by a second value.	All versions
MUL	Multiply	Multiply two values.	All versions
NEG	Negate	Take the opposite sign of a value.	All versions
SQRT	Square Root	Calculate the square root of a value.	Version 36 or later
SQR	Square Root	Calculate the square root of a value.	Version 35 or earlier
SUB	Subtract	Subtract two values.	All versions

Trigonometric

Rockwell Automation has not done independent mathematical analysis of the numerical algorithms in any of the following trigonometric instructions. If you require a specific degree of accuracy, you must functionally test this instruction over your expected input domain.

Mnemonic	Name	Description	Logix Designer Application
ACOS	Arc Cosine	Compute the arc-cosine of a number.	Version 36 or later
ACS	Arc Cosine	Compute the arc-cosine of a number.	Version 35 or earlier
ASIN	Arc Sine	Compute the arc-sine of a number.	Version 36 or later
ASN	Arc Sine	Compute the arc-sine of a number.	Version 35 or earlier
ATAN	Arc Tangent	Compute the arc tangent in radians of y/x based on the sign of a value to determine the correct quadrant.	Version 36 or later
ATN	Arc Tangent	Compute the arc tangent in radians of y/x based on the sign of a value to determine the correct quadrant.	Version 35 or earlier
ATAN2	Arc Tangent 2	Compute the arc tangent in radians of y/x based on the signs of both values to determine the correct quadrant.	All versions
COS	Cosine	Compute the cosine of a number.	All versions
SIN	Sine	Compute the sin of a number.	All versions
TAN	Tangent	Compute the tangent of a number.	All versions

I/O

For special considerations when using the GSV and SSV instructions, see the controller user manual.

Mnemonic	Name	Description	Logix Designer Application
GSV	Get System Value	Get controller status information.	All versions
SSV	Set System Value	Set controller status information.	All versions

Math Conversion

Mnemonic	Name	Description	Logix Designer Application
DEG	Degrees	Convert radians into degrees.	All versions
BCD_TO	Convert to Integer	Convert the BCD value to an integer value.	Version 36 or later
FRD	Convert to Integer	Convert the BCD value to an integer value.	Version 35 or earlier
RAD	Radian	Convert degrees into radians.	All versions
TO_BCD	Convert to BCD	Convert the integer value to a BCD value.	Version 36 or later
TOD	Convert to BCD	Convert the integer value to a BCD value.	Version 35 or earlier
TRUNC	Truncate	Remove the fractional part of a value.	Version 36 or later
TRN	Truncate	Remove the fractional part of a value.	Version 35 or earlier