Siemens SIMATIC S5 Manual page 141

S5-115F Manual
Example
A photoelectric barrier that
counts piece goods is installed at
input I 2.0. After every 100 pieces,
the program is to jump to FB 5 or
FB 6. After 800 pieces, counter 10
is to be reset automatically and
start counting again.
A photoelectric barrier that
counts piece goods is installed at
input I 10.0. After every 256
pieces, the counter is supposed to
be reset and start counting again.
Note
Times and counts are stored in the timer/counter word in hexadecimal notation in the
10 least significant bits (bits 0 to 9).
The time base is stored in bits 12 and 13 of the timer word.
EWA 4NEB 811 6149-02
STL
C DB 10
A I 2.0
CU C 10
A I 3.0
L KC 0
S C 10
O I 4.0
O F 5.2
R C 10
LC C 10
T DW 12
TBN D 12.8
JC FB 5
TB D 12.8
JC FB 6
TB D 12.11
= F 5.2
:A I 10.0
:CU C 20
:A I 11.0
:L KC 0
:S C 20
:TB C 20.8
:JC = FULL
:BEU
FULL:RU C 20.8
:BE
STEP 5 Operations
Explanation
Call data block 10.
Input I 3.0 loads the count of
counter 10 with the constant 0.
With each positive edge change at
I 2.0, the counter is incremented by
1. The counter is reset by either
input I 4.0 or flag F 5.2. The current
count of the counter is stored in
data word DW 12 in BCD code.
As long as bit 8 of data word DW 12
is zero, program processing jumps
to function block FB 5.
This is the case for the
counts 1, 3, 5 to 97, 99.
As long as bit 8 of data word DW 12
is "1", program scanning jumps to
function block FB 6.
This is the case for the
counts 2, 4, 6 to 98, 100.
When data bit 11 of data word
DW 12 becomes "1" (the count is
then 800), flag F 5.2 is set
conditionally.
Input I 11.0 loads the count of
counter 20 with the constant 0. The
count is incremented by 1 with each
positive edge change at input
I 10.0. If the count has reached
256 = 100 (bit 8 is "1"), program
H
scanning jumps to the label "FULL".
Otherwise the block is terminated.
Bit 8 of counter C 20 is set to "0"
unconditionally. Then the count is
again 000 .
H
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