Counter Operations - Siemens S5-100U User Manual

S5-100U
8.1.5

Counter Operations

The programmable controller uses counter operations to handle counting jobs. Counters can count
up and down. The counting range is from 0 to 999 (three decades). Table 8-5 provides an
overview of the counter operations. Examples follow the table.
Operation Operand
S
R
CU
CD
ID
C
Loading a Count
Counter operations call internal counters.
When a counter is set, the word in ACCU 1 is used as a count. You must therefore first store
counts in the accumulator.
You can load a count with any of the following data types:
KC constant count
or
DW data word
IW input word
QW output word
FW flag word
EWA 4NEB 812 6120-02
Table 8-5. Overview of Counter Operations
Set Counter
The counter is set on the leading edge of the RLO.
Reset Counter
The counter is set to zero as long as the RLO is "1".
Count Up
The count is incremented by 1 on the leading edge of the RLO.
When the RLO is "0", the count is not affected.
Count Down
The count is decremented by 1 on the leading edge of the RLO.
When the RLO is "0", the count is not affected.
Parameter CPU 100
0 to 15
Meaning
CPU 102
0 to 31
The data for these words must
be in BCD code.
STEP 5 Operations
CPU 103
0 to 127
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