Attention

IronPLC supports IEC 61131-3 Structured Text excluding I/O mapping.

Standard Library

IronPLC provides the standard functions and function blocks defined by IEC 61131-3. These are available in all programming languages.

Tip

Examples on supported function pages are interactive — you can edit and run them directly in the IronPLC Playground.

Functions

Function	Description
ABS	Absolute value
SQRT	Square root
LN	Natural logarithm
LOG	Base-10 logarithm
EXP	Natural exponential
EXPT	Exponentiation
SIN	Sine
COS	Cosine
TAN	Tangent
ASIN	Arc sine
ACOS	Arc cosine
ATAN	Arc tangent
ADD	Addition
SUB	Subtraction
MUL	Multiplication
DIV	Division
MOD	Modulo
GT	Greater than
GE	Greater than or equal
EQ	Equal
LE	Less than or equal
LT	Less than
NE	Not equal
SEL	Binary selection
MAX	Maximum
MIN	Minimum
LIMIT	Clamp to range
MUX	Multiplexer
SHL	Shift left
SHR	Shift right
ROL	Rotate left
ROR	Rotate right
LEN	String length
LEFT	Left substring
RIGHT	Right substring
MID	Middle substring
CONCAT	String concatenation
INSERT	String insertion
DELETE	String deletion
REPLACE	String replacement
FIND	String search
Type conversions	Type conversion functions

Function Blocks

Function Block	Description
TON	On-delay timer
TOF	Off-delay timer
TP	Pulse timer
CTU	Count up
CTD	Count down
CTUD	Count up/down
R_TRIG	Rising edge detection
F_TRIG	Falling edge detection
SR	Set/reset flip-flop
RS	Reset/set flip-flop