Mitsubishi Electric melsec q00ujcpu User Manual page 167

(5) Precautions
(a) Initial clock data setting
No clock data is set at the factory.
Clock data is required for some functions of the CPU module used in the system, such as error
history storage, or for intelligent function modules.
Before using the CPU module for the first time, set the time correctly.
(b) Clock data correction
If a part of the clock data is corrected, the entire clock data must be rewritten to the CPU module.
(c) Clock data setting range
When changing clock data, write data within the range given in
If impossible time data is written to the CPU module, normal clock operation cannot be performed.
However, the CPU module does not detect an error if the impossible time data is within the range.
Write operation to the CPU module
February 30
32 of month 13
(d) Use for clock data of 1/1000 sec.
1) Function that clock data of 1/1000 sec. can be used
Only the following instructions can use the clock data of 1/1000 sec.
• S(P).DATERD
• S(P).DATE+
• S(P).DATE-
Other instructions cannot use the clock data of 1/1000 sec.
(Such as for reading data by SM/SD, storing the time of error occurrence as error history data, reading data
by GX Developer, or reading data by dedicated instructions of other modules.)
2) When clock data is changed
When clock data is changed by GX Developer or instructions (including dedicated instruction of other
modules), the clock of 1/1000 sec. is reset to 0.
(6) Clock data accuracy
Accuracy of the clock data varies depending on the ambient temperature as shown below.
(7) Clock data comparison
To compare clock data in a sequence program, read the clock data with the DATERD instruction (instruction for
reading clock data).
Since the DATERD instruction reads the year data in four digits, the data can be compared by the comparison
instruction without any modifications.
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Table6.5 Example of clock data
Executed
Not executed
Table6.6 Clock data accuracy
Ambient temperature ( )
0
+ 25
+ 55
CPU module operation
An error is not detected.
When the DATEWR instruction is executed, "OPERATION ERROR" (error
code: 4100) is detected.
When SM210 is turned on, SM211 turns on.
(3) in this section.
Accuracy (Day difference, S)
-2.96 to +3.74 (TYP.+1.42)
-3.18 to +3.74 (TYP.+1.50)
-13.20 to +2.12 (TYP.-3.54)