Siemens SIMATIC S5-100U, System Manual

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S5-100U STEP 5 Operations
STL Explanation Example
A photoelectric barrier that counts
piece goods is installed at input
I 0.0. After every 100 pieces, the
program is to jump to FB5 or FB6.
After 800 pieces, counter 10 is to
be reset automatically and start
counting again.
C DB 10
A I 0.0
CU C 10
A I 0.1
L KC 000
S C 10
O I 0.2
O F 5.2
R C 10
LD 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
Call data block 10.
Input I 0.1 loads the count of
counter 10 with the constant 0. With
each positive edge change at I 0.0,
the counter is incremented by 1. The
counter is reset by either input I 0.2
or flag F 5.2.
The current count of the counter is
stored in data word DW12 in BCD
code.
As long as bit 8 of data word DW12
is zero, program processing jumps to
function block FB5. This is the case
for the first, third, fifth etc. batch of
100 pieces.
As long as bit 8 of data word DW12
is “1”, program scanning jumps to
function block FB 6. This is the case
for the second, fourth, sixth, etc.
batch of 100 pieces.
When data bit 11 of data word DW12
becomes “1” (the count is then 800),
flag F 5.2 is set conditionally.
Input I 0.4 loads the count of counter
20 with the constant 0. The count is
incremented by 1 with each positive
edge change at input I 0.3. If the
count has reached 256 = 100
H
(bit 8
is “1”), program 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
.
A photoelectric barrier that counts
piece goods is installed at input
I 0.3. After every 256 pieces, the
counter is supposed to be reset and
start counting again.
:A I 0.3
:CU C 2
:A I 0.4
:L KC 000
:S C 20
:TB C 20.8
:JC = FULL
:BEU
FULL:RU C 20.8
:BE
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 812 6120-02b
8-43