Program Number

It is necessary to provide a program number as an identification for each of the program that is stored in the memory of the controller. For this purpose, O word address is used with a maximum of four digits. It must be given as the first block in the program.

O 1235;           Program start

Care must be exercised in giving the program number. If a program is stored in the memory with the same number it will be simply replaced without a warning.

Block Number

It is also necessary to provide an identification label for each of the blocks to help with any editing or reference purposes. The N word address is used for this purpose. However, it is not necessary to provide a block number for all the blocks. The block numbers need not be in any particular sequence, though it helps a human programmer to read it if it follows a sequence.

It is generally suggested that the sequence numbers may be assigned in intervals of five or ten which will help to insert additional blocks when necessary.