Programming The Operating Hours Counter - Siemens SIMATIC S5-100U System Manual

The Integral Real-Time Clock

12.7.3 Programming the Operating Hours Counter

You can enable the operating hours counter with bit 9 of the status word. This allows you to
establish, for example, the number of hours a motor has been in operation. The operating hours
counter is active only in the RUN mode.
Transferring Settings to the Operating Hours Counter
You can preset the operating hours counter with a certain start value (e.g. after exchanging the
CPU).
• The clock data must be transferred in BCD code.
TIP: The "KC" data format loads a BCD constant into ACCU 1 and is therefore especially
suitable for entering the settings.
• If you do not want a value (for example minutes) to be transferred, entering the relevant byte as
"255 " or "FF ". The current value for this variable is then retained.
D H
• After you have transferred the settings to the clock data area, you must set bit 10 in the status
word for the clock to accept the clock data.
• Bit 8 in the status word displays incorrect settings.
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S5-100U
EWA 4NEB 812 6120-02b