Siemens CPU 948 Programming Manual page 119

Programming Examples in the STL, LAD and CSF Methods of Representation
Comparison operations
Compare for equal to
Logical/circuit diagram
IB19 IB20
V1 V2
=
=
Q 3.0
The first operand is compared with the second operand
by the comparison operation. The RLO of the comparison
is binary.
RLO = "1": comparison is satisfied if ACCU-1-L = ACCU-2-L
RLO = "0": comparison is not satisfied, when ACCU-1-L is
not equal to ACCU-2-L.
The condition codes CC1 and CC0 are set as described
in the list of operations.
ACCU-2-H and ACCU-1-H are not involved in the operation
for a 16-bit fixed point comparison.
In a 32-bit fixed point comparison (! = D) and floating point
comparison (! = G) the entire contents of ACCU 1 and
ACCU 2 (32 bits) are compared with each other.
During the comparison, the numerical representation of the
operands is taken into account, i.e. the contents of ACCU-1-L
and ACCU-2-L are interpreted here as a fixed point number.
CPU 948 Programming Guide
C79000-G8576-C848-04
STEP 5 representation
Statement Ladder
list diagram
I B19
L
L IB20
IB19 V1
! =
! = F
IB20 V2
= Q 3.0
Control system
flowchart
F IB19 C1
! =
Q 3.0
Q IB20 C2
F
Q Q 3.0
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