On PLCs which support debugging either in simulation or on the hardware it is also possible to add explicitly programmed breakpoints using the BRK instruction. These breakpoints can be activated by the programming algorithm or by enabling the execution condition by monitoring.
When downloading BRK instruction to PLCs which support debugging only in the simulation:
16-bit PLCs which support debugging only in the simulation, a syntax error occurs. For these PLCs the compiler always generates a warning message. Before downloading such a program to the PLC, the BRK instruction must be commented out.
32-bit PLCs accept the BRK instruction, but it is never executed.