A method is provided for processing a software project comprising a primary code and a machine code on a first processing station by a user. The method comprises downloading a first copy of the primary code from a first memory to the first processing station, modifying the first copy of the primary code, and generating a first program version of the machine code, where the first program version of the machine code is generated from the first copy of the primary code, uploading the first program version of the machine code to a second memory, and automatically uploading the modified copy of the primary code into the first memory, triggered by the upload of the first program version of the machine code into the second memory.

A method for agricultural refill planning determines a refill time and access point for a mobile storage device (e.g., a seed tender) to refill an agricultural distribution device (e.g., planter) with agricultural material (e.g., seed). The refill time and access point are selected so that excess time is not lost and areas, such as planting fields, are not adversely affected by movement of the agricultural distribution device or the mobile storage device.

A safety control unit includes: a memory; a computation control part; and an input and output unit for connecting the computation control part to a safety input device and an output device to be safely controlled. A system program includes a data refresh program for executing a data refresh of safety control data of the safety input device and the output device and the control data of the memory via the input and output unit. If the computation control part receives a change of a control program, the computation control part stops executing the control program. The computation control part executes the change of the control program while executing a part of the system program including the data refresh. The computation control part resumes executing the control program.

A method is provided for processing a software project comprising a primary code and a machine code on a first processing station by a user. The method comprises downloading a first copy of the primary code from a first memory to the first processing station, modifying the first copy of the primary code, and generating a first program version of the machine code, where the first program version of the machine code is generated from the first copy of the primary code, uploading the first program version of the machine code to a second memory, and automatically uploading the modified copy of the primary code into the first memory, triggered by the upload of the first program version of the machine code into the second memory.

The purpose of the invention is the simplification of a task of changing a control program upon a control device which is in use. A support device comprises: a computing part computing, for each unit program which configures a control program, identification information according to the content of each of the unit programs; a first transferring part transferring the unit programs and the identification information which is associated with the unit programs to a control device; a generating part generating changed unit programs according to a change operation upon any of the unit programs which configure the control program; and a second transferring part transferring the changed unit programs to a control device which is in use on condition that identification information is present on the control device which is identical to the identification information which is associated with the unit programs which configure the control program.

An execution code of a user program applicable to a PLC is fitted and arranged to an adequate block among memory blocks of variable sizes, and execution order and position information of each execution code are downloaded to the PLC along with recorded execution table. A CPU module of PLC sequentially executes each execution code randomly arranged on a memory with reference to the execution table. Because an execution code is loaded on a memory block having respectively different sizes such as N, 2N and 4N, utilization of non-use space can be improved over a conventional allocation method of fixed size. An execution table is utilized to discontinuously configure a program execution area, whereby a user program can be easily modified or added during PLC operation.

A user program for a safety controller is created by means of a program editor. The user program has a first program portion and at least one additional program portion. The first program portion defines safety-related logical dependencies between selected sensor signals and actuator signals. The user program is compiled and linked, in order to obtain an executable original program code. The original program code is transferred to a first memory of the safety controller and executed by a processor of the safety controller. The first program portion may be modified and compiled in order to obtain a modified first code portion. The modified first code portion is transferred to a second memory of the safety controller while the original program code is executed. The modified first code portion is then executed in addition to the original additional code portion and instead of the original first code portion.

A method for agricultural refill planning determines a refill time and access point for a mobile storage device (e.g., a seed tender) to refill an agricultural distribution device (e.g., planter) with agricultural material (e.g., seed). The refill time and access point are selected so that excess time is not lost and areas, such as planting fields, are not adversely affected by movement of the agricultural distribution device or the mobile storage device.

A safety control unit includes: a memory; a computation control part; and an input and output unit for connecting the computation control part to a safety input device and an output device to be safely controlled. A system program includes a data refresh program for executing a data refresh of safety control data of the safety input device and the output device and the control data of the memory via the input and output unit. If the computation control part receives a change of a control program, the computation control part stops executing the control program. The computation control part executes the change of the control program while executing a part of the system program including the data refresh. The computation control part resumes executing the control program.

A programmable logic controller capable of improving the expandability of a distributed control system and a programming tool for the programmable logic controller are provided. A programmable logic controller (PLC) that constitutes a distributed control system includes: a variable table that includes variable information including identification symbols for identification of a plurality of PLCs and variable names of reference variables, the variable information being set for each of the reference variables; a storage device that has a memory region for storing the reference variables; and an interface circuit that mutually converts communication data for use in communication between the PLC and a different PLC and the reference variables stored in the memory region. The reference variables are variables mutually referenced by the plurality of PLCs.