226 Rockwell Automation Publication 1756-RM003N-EN-P - October 2011
Chapter 5 Compare Instructions (CMP, EQU, GEQ, GRT, LEQ, LES, LIM, MEQ, NEQ)
Equal To (EQU)
The EQU instruction tests whether Source A is equal to Source B.
Operands:
Relay Ladder
· If you enter a SINT or INT tag, the value converts to a DINT value by
sign-extension.
· REAL values are rarely absolutely equal. If you need to determine the
equality of two REAL values, use the LIM instruction.
· String data types are:
– default STRING data type.
– any new string data type that you create.
· To test the characters of a string, enter a string tag for both Source A and
Source B.
Structured Text
Use the equal sign ‘=’ as an operator within an expression. This expression
evaluates whether sourceA is equal to sourceB.
See Structured Text Programming
for information on the syntax of expressions
within structured text.
Operand Type Format Description
Source A SINT
INT
DINT
REAL
string
Immediate Tag Value to test against
Source B
Source B SINT
INT
DINT
REAL
string
Immediate Tag Value to test against
Source A
IF sourceA = sourceB THEN
<statements>;
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