A programmable controller includes a command execution unit that executes multiple commands in a user program in order; a database storage unit that stores therein a database that holds data used in a process performed by the command execution unit in a table format; a database-query-command generation unit that, when the commands include a command to access the database, converts the access command into a database query command described in a database query language; and a database management unit that accesses the database in the database storage unit and acquires data specified by the database query command.

One or more techniques and/or systems are disclosed for a center frame positioning method for an agricultural sprayer. The method comprises activating a center frame positioning system and collecting and processing position data related to a position of a suspended center frame in the center frame positioning system. The method further comprises evaluating the position data to determine whether any adjustment to the position of the suspended center frame is needed and controlling actuator force in at least one actuator to adjust the position of the suspended center frame based on the evaluating the position data.

A data management system includes: a plurality of controllers that each output control data updated by a data updating device that updates the control data and data related information to a network, the control data being data necessary for controlling a device to be controlled, the data related information being information related to the updated control data and including at least date and time information being information on a date and time when the control data are updated; and a data management device that is connected with the plurality of controllers via the network, acquires the control data and the data related information output from each of the controllers, and accumulates the control data and the data related information in association with each other.

A data management system includes: a plurality of controllers that each output control data updated by a data updating device that updates the control data and data related information to a network, the control data being data necessary for controlling a device to be controlled, the data related information being information related to the updated control data and including at least date and time information being information on a date and time when the control data are updated; and a data management device that is connected with the plurality of controllers via the network, acquires the control data and the data related information output from each of the controllers, and accumulates the control data and the data related information in association with each other.

One or more techniques and/or systems are disclosed for a center frame positioning method for an agricultural sprayer. The method comprises activating a center frame positioning system and collecting and processing position data related to a position of a suspended center frame in the center frame positioning system. The method further comprises evaluating the position data to determine whether any adjustment to the position of the suspended center frame is needed and controlling actuator force in at least one actuator to adjust the position of the suspended center frame based on the evaluating the position data.