Siemens SIMATIC S5 Manual page 113

S5-115F Manual
Loading a time
Timer operations call internal timers.
When a timer operation is started, the word in ACCUM 1 is used as a time value.
You must therefore first specify time values in the accumulator.
You can load a timer with any of the following data types:
KT constant time value
or
DW data word
IW input word
QW output word
FW flag word
Loading a constant time value
The following example shows how you can load a time value of 40 sec.
L KT 40.2
Key for time base:
Base 0
Factor 0.01 sec.
Example: KT 40.2 corresponds to 40 x 1 sec.
Tolerances:
The time tolerance is calculated as the sum of the time base and the maximum interval between
the FB 254 SYNC synchronization block calls.
Examples
Possible settings
for the time
40 sec.
Note
Always use the smallest time base possible. You achieve more accurate times in this
way.
EWA 4NEB 811 6149-02
These data types must be
in BCD code.
Operation
Operand
Coded time base (0 to 3)
Time (0 to 999)
1 2
0.1 sec. 1 sec.
Operand
KT 400.1 400 x 0.1 sec.±
KT 40.2 40 x 1 sec. ±
KT 4.3 4 x 10 sec. ±
3
10 sec.
Time Interval
0.1 sec.
1 sec.
10 sec.
STEP 5 Operations
39.9 sec. ... 40.1 sec.
39 sec. ... 41 sec.
30 sec. ... 50 sec.
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