User Manual
Chapter 11
GFK-1503F
Jan 2020
The Service Request Function
184
Figure 185
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
