Programmable controller, peripheral device thereof, and table data access program of programmable controller

A programmable controller comprising:

• a command execution unit to execute multiple commands in a user program in order;
• a database storage unit to store therein a database that holds data used in a process performed by the command execution unit in a table format;
• a system-data storage unit to store therein database-access setting information that sets a condition acquiring data included in the database in the database storage unit;
• a database-query-command generation unit, when the commands include an instruction to access a database, to convert the database-access setting information in the system-data storage unit into a database query command described in a database query language;
• and
• a database management unit
• to access the database in the database storage unit, and
• to access data specified by the database query command, wherein
• the database-access setting information includes
• database specification information that specifies the database in the database storage unit and
• an access-target specification condition that includes a name of a table of the database, and
• the database-query-command generation unit generates the database query command from the database-access setting information in accordance with command conversion information in which information included in the database-access setting information corresponds to a parameter of the database query command.

A table data access program for use with a programmable controller, wherein

• the programmable controller includes a user-data storage unit, and a database storage unit that stores therein a database that holds data used in a process of executing a normal command in a table format,
• the programmable controller repeatedly executes commands of a user program in order from a first normal command to an END command described at an end of the commands and accesses the database in the process of executing a normal command, and
• the programmable controller accesses the database when the normal command is executed,
• the table data access program, when executed, causing the programmable controller to execute:
• a database-query-command generation procedure of, when the normal command includes a command to access the database, converting the access command into a database query command described in a database query language;
• a database management procedure of
• accessing the database in the database storage unit and
• accessing data in the database specified by the database query command so as to perform a predetermined process, and
• an END command processing procedure of executing an END command including a process of acquiring the result of executing the database query command, wherein
• in the END command processing procedure,
• when a process corresponding to the database query command issued is completed, a completion checking process of writing the data acquired by the database management procedure in an address specified by the command to access the database of the user-data storage unit is performed, and
• when the process corresponding to the database query command issued is not completed, the completion checking process is performed at a time of executing a next END command.

A table data access program for use with a programmable controller, wherein

• the programmable controller includes a user-data storage unit, a database storage unit that stores therein a database that holds data used in a process of executing a normal command in a table format, and a system-data storage unit that stores therein database-access setting information that sets a condition acquiring data included in the database in the database storage unit,
• the programmable controller repeatedly executes commands of a user program in order from a first normal command to an END command described at an end of the commands, and
• the programmable controller accesses the database when the normal command is executed,
• the table data access program, when executed, causing the programmable controller to execute:
• a database-query-command generation procedure of, when the normal command includes an instruction to access a database, converting the database-access setting information in the system-data storage unit into a database query command described in a database query language;
• and
• a database management procedure of
• accessing the database in the database storage unit and
• accessing data specified by the database query command so as to perform a predetermined process, wherein
• the database-access setting information includes
• database specification information that specifies the database in the database storage unit and
• an access-target specification condition that includes a name of a table of the database, and
• the database-query-command generation unit generates the database query command from the database-access setting information in accordance with command conversion information in which information included in the database-access setting information corresponds to a parameter of the database query command.