Siemens CPU 948 - Page 117

Counter operations
(continued)
I 4.1
RS
CQ
CI
+
binary
16 bits
CD
BI
DE
RQ
C1
CU
S
CV
Owing to the two separate edge flags for CU and CD,
a counter with two different inputs can be used as an
up/down counter.
The value of the addressed counter is incremented
by "1" to a maximum value of 999. The function CU
is only executed on a positive edge (from "0" to "1")
of the logic operation programmed before CU. The
flags necessary for edge evaluation of the counter
inputs are incorporated in the counter word.
I 4.1
A
I
4.1
CU C 1
CD
DU
DE
RQ
C1
CU
S
CV
I 4.1
Logical/circuit diagram
STEP 5 representation
Ladder Control system
Statement
list
Count up
diagram flowchart
Programming Examples in the STL, LAD and CSF Methods of Representation
CPU 948 Programming Guide
C79000-G8576-C848-04
3 - 45