3.1.6 Comparison Operations - Siemens SIMATIC S5 Manual

S5-115F Manual

3.1.6 Comparison Operations

Comparison operations compare the contents of the two accumulators. The comparison does not
change the accumulators' contents. Table 3-6 provides an overview of the comparison operations.
An example follows the table.
Operation Operand
! = F
> < F
> F
> = F
< F
< = F
Processing comparison operations
To compare two operands, load them consecutively into the two accumulators.
Execution of the operations is independent of the RLO. The result is binary and is available as RLO
for further program scanning. If the comparison is satisfied, the RLO is "1". Otherwise it is "0".
Executing the comparison operations sets the condition codes ( 3.4).
Note
When using comparison operations, make sure the operands have the same number
format.
EWA 4NEB 811 6149-02
Table 3-6. Overview of Comparison Operations
Compare for "equal to".
The contents of the two accumulators are interpreted as bit
patterns and scanned to see if they are equal.
Compare for "not equal to".
The contents of the two accumulators are interpreted as bit
patterns and compared to see if they are not equal.
Compare for "greater than".
The contents of the two accumulators are interpreted as fixed-
point numbers. They are compared to see if the operand in
ACCUM 2 is greater than the operand in ACCUM 1.
Compare for "greater than or equal to".
The contents of the two accumulators are interpreted as fixed-
point numbers. They are compared to see if the operand in
ACCUM 2 is greater than or equal to the operand in ACCUM 1.
Compare for "less than".
The contents of the two accumulators are interpreted as fixed-
point numbers. They are compared to see if the operand in
ACCUM 2 is less than the operand in ACCUM 1.
Compare for "less than or equal to".
The contents of the two accumulators are interpreted as fixed-
point numbers. They are compared to see if the operand in
ACCUM 2 is less than or equal to the operand in ACCUM 1.
Meaning
STEP 5 Operations
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