Siemens SIMATIC S5-95F Manual page 208

STEP 5 Operations
Resetting a Counter "R" and Counting Up "CU"
Example: When input I 0.0 is switched on, the count in counter 1 is incremented by 1. As long as
a second input (I 0.1) is "1", the count is reset to "0".
The A C 1 operation results in signal state "1" at output Q 1.0 as long as the count is
not "0".
1
0
1
0
2
0
1
0
STL
A I 0.0
CU C 1
NOP 0
NOP 0
NOP 0
A I 0.1
R C 1
NOP 0
NOP 0
A C 1
= Q 1.0
8-28
Timing Diagram
I 0.0
I 0.1
C 1
Q 1.0
Time
R C1
CSF
C 1
I 0.0
CU
CD
S
CV BI
DE
I 0.1
R Q
I 0.1
I 0.0
I 0.0
I 0.1
Q 1.0
S5-95F
Circuit Diagram
R S CI
I I I I
Binary
CQ
16 bits
0
Q 1.0
LAD
C 1
CU
CD
S
CV BI
DE
R Q
Q 1.0
EWA 4NEB 812 6210-02