Siemens SIMATIC S7-200 - Counter Example

IEC 1131-3 Instructions
10-17
S7-200 Programmable Controller System Manual
A5E00066097-02
Note
Since there is one current value for each counter, do not assign the same number
to more than one counter. (Up Counters, Down Counters, and Up/Down Counters
access the same current value.)
Inputs/Outputs Operands Data Types
CU, CD, R, LD
(LAD only)
Power Flow BOOL
CU, CD, R, LD
(FBD only)
I, Q, M, SM, V, S, L, T, C, Power Flow BOOL
PV (LAD & FBD) VW, IW, QW, MW, SMW, LW, SW, AIW, AC, Constant, *VD,
*AC, *LD
INT
QU (LAD & FBD) I, Q, M, SM, V, S, L BOOL
QD (LAD & FBD) I, Q, M, SM, V, S, L BOOL
CV (LAD & FBD) VW, IW, QW, MW, SW, LW, AC, *VD, *AC, *LD INT
Cxxx Constant CTUD
Counter Example
I4.0
CU-Up
Timing Diagram
LAD FBD
I3.0
CD-Down
%I4.0
%C48
%I3.0
4
%I2.0
CTUD
CU
R
CD
PV
I2.0
R-Reset
0
1
2
3
4
3
4
0
VW0
CV-current
Q0.0
QU-Up
QU
CV
QD
Input
CTUD
>CU
R
>CD
PV
QU
CV
QD
%I4.0
%I3.0
%I2.0
LD
LD
4
I1.0
LD-Load
Q0.1
QD-Down
%I1.0
%Q0.0
%Q0.1
%VW0
%C48
%Q0.1
%VW0
+4
2
3
4
%Q0.0
Figure 10-6 Example of Counter Instruction for LAD and FBD