Programmable logic controller having program for designating addresses of memory to which data indicating operating statuses of machine arc to be stored

A programmable logic controller for sequence-controlling an industrial machine, comprising:

• processor means executing a non-editable system program and an editable user program;
• memory means storing a first data group to be used in executing the system program and a second data group to be used in executing the user program in respective predetermined addresses, the respective data of the first data group being assigned to a specific addresses of said memory means;
• address storage means storing a designated relationship between the respective addresses of said memory means in which the second data group is to be stored, and the addresses of said memory means which are assigned to respective data of the first data group, wherein said processor means transfers necessary signals for executing said user program through said address storage means;
• and
• I/O module group means for transferring signals to and from peripheral equipment, the system program including a program designating the addresses of said memory means to which data indicating various operating statuses of the industrial machine are to be stored, and the addresses to which signals transferred between each input and output terminal of said I/O module group means and the peripheral equipment are to be stored.