Siemens SIMATIC S5-115U, User Manual

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S5-115U Manual Integral Real-Time Clock
Storing the Current Time/Date After a RUN/STOP Change
Note
This clock data area is only written to if
• bit 5 in the status word is set to "1"
• a RUN/STOP change or a POWER OFF has taken place
• the necessary memory space is available in the operand area
This enables you to detect a RUN/STOP change or a POWER OFF even if the PC has since gone back
to RUN mode. The time and date of the last RUN/STOP change or POWER OFF are in words
18 to 21 (cf.Table 13-3).
If several RUN/STOP changes have occurred before you read out this clock data area, you will only
be able to determine the time of the last change.
If you do not have sufficient memory for this clock data area, you cannot use this area or only part
of it. This has no other effects.
Programming the Prompt Function
Transferring Settings to the Clock
• The settings are stored in the clock data area using Transfer operations (cf. Table 13-5).
• The AM/PM flag (bit No. 7) is only significant in 12-hour mode
Bit 7=1 PM
Bit 7=0 AM
• The clock data must be transferred in BCD.
Note
The "KC" data format loads a BCD constant into accumulator 1 and is therefore
especially suitable for entering settings.
• If you enter the number "255
D
" or "FF
H
" in a byte in the prompting time, this byte will be
ignored when evaluating "Prompt time reached". This makes it easy to program, for example,
a prompt which is repeated daily by entering the value "255
D
or FF
H
" in the "Weekday",
"Date" and "Month" variables.
• Transfer of the prompt function settings to the clock is initiated by bit 14 in the status word.
• Incorrect settings are flagged by bit 12 in the status word.
EWA 4NEB 811 6130-02b
13-19