Siemens SIMATIC S5-100U System Manual page 320

The Integral Real-Time Clock
Possible errors:
- Clock is not
available.
- Clock system data
is incorrect or not
available.
- Clock data area is
too small.
- Clock is defective.
The clock cannot be
used.
Eliminate the errors.
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The lower portion of the flowchart has only a diagnostic function. There is nothing you must perform.
You can also implement the upper portion of the flowchart using the FORCE VAR programmer function
(programmable controller in the RUN mode) or using the FORCE function (the programmable controller
is in the STOP mode and bit 4 = 1 in the status word).
Figure 12-7. Flowchart - Transferring Time and Date Settings to the Clock
If you do not want a value (for example the minutes) in the settings to be transferred, enter the value
for relevant byte as either 255
retained.
Incorrect settings are displayed by a set bit 0 in the status word. The clock continues to run with the
old values.
In a similar manner, you can program new settings for the time prompt function and the operating
hours counter. However, the settings are located in other data words in the clock data area. See
section 12-4. You must set the respective bit to 1 in the status word so that the clock can accept
the new settings. See section 12-5.
12-20
Write the settings into the
clock data area
Set transfer bit 2 in the
control program
Wait approximately two seconds
(entering a wait program)
yes
Status Word
Bit 2=1
no
Status Word
Bit 0=1
no
The clock runs with
the new settings.
or FF . When you set the clock, the old value present in the clock is
D H
yes
Incorrect settings
The clock continues
running with the old
values.
EWA 4NEB 812 6120-02b
S5-100U
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