Clock Data Accuracy; Setting Clock Data For The First Time; Setting Clock Data When No Battery Is Installed; Correcting Clock Data - Mitsubishi Electric Q12DCCPU-V User Manual

4
FUNCTIONS

(5) Clock data accuracy

(6) Precautions
4
- 31 4.7 Clock Function
(a) While the C Controller module is ON
• The clock function accuracy is the same as that of the VxWorks POSIX
Clock.
A higher frequency of interrupt program execution may cause a longer clock
delay, depending on the system configuration of the C Controller module.
For details of POSIX Clock, refer to the following.
Manual for VxWorks
• When correcting the clock data, make them synchronized with the clock of
the SNTP server computer on the network, using the user program.
Obtain clock data from the SNTP server computer, and refer to the sample
program (SntpTimeSet.c) for setting clock data.
(b) While the C Controller module is OFF
The clock function accuracy varies depending on the ambient temperature of the
C Controller module. (
(a) Setting clock data for the first time
No clock data are set for the C Controller module prior to shipping.
Clock data are used by the C Controller module's system, such as event history,
and intelligent function modules.
Therefore, before using the C Controller module for the first time, be sure to set
accurate clock time.
(b) Setting clock data when no battery is installed
If no battery is installed in the C Controller module, clock data must be set.
Otherwise, clock data will be incorrect while the C Controller module is ON.
(c) Correcting clock data
1) Even if a part of clock data is to be corrected, all of clock data must be written
to the C Controller module again.
2) If the year 2100 is reached after clock setting, clock data of the year 2100 can
be used until restart of the C Controller module.
Set them again to the year 2000 to 2099 when restarting the C Controller
module.
3) The C Controller module's clock must set with the QBF_WaitEvent or
QBF_WaitUnitEvent function not being executed.
Page 3-2, Section 3.2)