Need Help!- Level vs. sub program

[mr_electrician]

Hello, can anyone tell me the difference between a ladder level and a sub program. Also why and when would you use one over another?

[viorel26]

A subprogram is a program called by the second-level Ladder
program. It is a program unit starting with the functional instruction SP and ending with the functional instruction SPE. Up to 512 subprograms can be created for one PMC.

[mr_electrician]

Originally Posted by viorel26 A subprogram is a program called by the second-level Ladder program. It is a program unit starting with the functional instruction SP and ending with the functional instruction SPE. Up to 512 subprograms can be created for one PMC.

I want to add an external device to our lathe (automated loader). I want to have the plc program seperated from the rest of the plc program. Should I create a new lever or should I create a new sub program? Also, do I have to call up a new level somewhere?