PLC Program memory calculation

[Anup29]

While selecting a PLC , what is thumb rule for program memory calculation?,
Or
How do we select memory size for PLC?

 

[spaderkung]

Experience or contact maker.
Different for each plc and all different types of memory. IO, code, data ...

 

[thingstodo]

+1 for @spaderkung

Particularly now that some of the PLC vendors are storing the documentation for the program, as well as the actual code, on the PLC. It is *VERY* handy, but it takes MUCH more room than the program!

 

[Steve Bailey]

A PLC will be designed to have enough memory for the programs likely to written for the amount of I/O it can support. So unless you know ahead of time that the program you plan to write will require an unusual amount of memory, any PLC that can handle your I/O will also be able to handle your program.