Omron NX701-1620 User Manual page 210

Appendix A
 When the value of the Timeout input variable is outside the valid range
 When the executed SQL statement resulted in an error in the DB
 When the combination of data types is not listed in the table of data type correspondence between
NJ/NX-series Controllers and database and the data type cannot be converted
 When the DB Connection Service cannot communicate with the DB due to a network failure or other
causes
 When the SQL statement cannot be spooled because the Spool capacity is exceeded
 When one or more SQL statements are already stored in the Spool memory
 When the instruction was not completed within the time specified in the TimeOut input variable
 When the instruction was executed before completion of the DB's processing for the DB Connection
Instruction Execution Timeout that occurred for the previous DB_Insert, DB_Update, DB_Select, or
DB_Delete instruction
 When more than 32 DB Connection Instructions were executed at the same time
Sample Programming
This section gives sample programming for the following operations.
 Insert production data into a specified DB when the trigger variable changes to TRUE.
 Update production data in a specified DB when the trigger variable changes to TRUE.
DB Connection Settings and Data Type Definition
The minimum settings necessary for the sample programming are shown below.
 DB Connection Settings
DB Connection name: MyDatabase1
 Structure Data Type Definition
Name
PRODUCTION_INSERT
Name
LotNo
Status
ProductionDate
Name
PRODUCTION_UPDATE
Status
FinishTime
Ladder Diagram
 Main Variables
Name
_DBC_Status
DB_Connect_instance
MyDB1
Trigger_Connect
A-22
Data type
STRUCT
STRING[256]
STRING[32]
STRING[8]
DATE
Data type
STRUCT
STRING[8]
DATE_AND_TIME
Data type
_sDBC_STATUS
DB_Connect
DWORD
BOOL
NJ/NX-series Database Connection CPU Units User's Manual (W527)
Initial value
--- System-defined variable that shows the
status of the DB Connection Service
--- Instance of DB_Connect instruction
--- This variable is assigned to the
DBConnection output variable from
DB_Connect_instance.
FALSE Variable used as a trigger for
establishing a DB Connection
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