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11.8 SVCREQ 7: Read or Change the Time-of-Day Clock
Use SVCREQ 7 to read or change the time of day clock in the PLC. The data can be
either BCD or ASCII. Either 2-digit-year or 4-digit-year format is available. The function
is successful unless some number other than 0 (read) or 1 (change) is entered for the
requested operation, or an invalid data format is specified, or data is provided in an
unexpected format.
11.8.1 Parameter Block Format for SVCREQ 7
For the date/time functions, the length of the parameter block depends on the data format.
The data block is either BCD or ASCII. BCD format requires 6 words; packed ASCII
requires 12 words (13 words for 4-digit year). For both data types:
• Hours are stored in 24-hour format.
• Day of the week is a numeric value from 1 (Sunday) to 7 (Saturday).
2-Digit Year Format 4-Digit Year Format
address
0 = read time and date 0 = read time and date
1 = set time and date 1 = set time and date
a 1
1 = BCD format 81h = BCD format
3 = packed ASCII format 83h = packed ASCII format
a 2 to
end
data data
Words 3 to the end of the parameter block contain output data returned by a read function,
or new data being supplied by a change function. In both cases, format of these data
words is the same. When reading the date and time, words (a 2) to the end of the
parameter block are ignored on input.
The Service Request Function GFK-1503E User Manual 205
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