Mitsubishi Electric MELSEC iQ-R Series Programming Manual page 987

Processing details
• These instructions execute the rollback in relation to the database corresponding to the identification number specified by
(s).
• Upon normal completion, the completion signal in the completion device (d1) is turned on and 0 is stored as the completion
status in the device (d2).
• The following figure shows the operation of the completion device at completion of the DBROLBAK(P) instruction.
Program
DBROLBAK(P) instruction
Completion device (d1)
Completion device (d1)+1
• SM753 (File being accessed) turns on while the DBROLBAK(P) instruction is executed.
DBROLBAK(P) instruction cannot be executed. If executed, no processing is performed. However, the instruction has been
completed with an error while the database access instruction is being executed.
• When "To Use or Not to Use the Built-in Database Access" is set to "Use" in the module parameter of the CPU module, the
DBROLBAK(P) instruction cannot be executed while SM1498 (CPU module database start-up flag) is off.
processing is performed.
*1 For the firmware versions supporting SM753 and SM1498, refer to the list of special relay areas. ( MELSEC iQ-R CPU Module
User's Manual (Application))
Precautions
In the following cases, the error completion signal in (d1)+1 is turned on and an error code is stored as the completion status
in the device (d2).
• The DBROLBAK(P) instruction is executed during execution of the database access instruction.
• An identification number outside the specified range is specified.
• The DBROLBAK(P) instruction is executed while no transaction is going on.
• The identification number of a database which is not open is specified by (s).
Operation error
Error code Description
(SD0)
2820H The area specified by (d1) exceeds the applicable range of the device/label used.
For the error code stored in the completion status of the operand, refer to the following.
Page 986 Error codes related to database access instructions
END processing
OFF
OFF
Performing the
rollback
END processing END processing
ON
Error completion
ON
*1
While SM753 is on, the
7 APPLICATION INSTRUCTIONS
7.21 Database Access Instructions
7
*1
If executed, no
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