On which module is the PLC startup mode set?

The startup mode of the plc is set in the startup characteristics (SETUP) option of the CPU module parameters. Hot start (Hotrestart), warm start (Warmrestart), and cold start (Clodrestart) are the names of three new startup modes defined by the S7 series PLC according to the EN61131 standard when the PLC-CPU restarts. In the S7 series PLC, the startup process of the three startup modes is as follows:

Hot start: When the PLC-CPU restarts, before executing the main cycle OB1, the organization block OB101 is processed first. All CPU data are backed up at startup, and the contents of all data areas (including timers, counters, flag registers, etc., regardless of the retention area and non-retention area) are all retained.

Warm start: When the PLC-CPU restarts, before executing the main loop OB1, the organization block OB100 is processed first. At startup, the contents of all PLC data blocks (DB) are retained; the contents of retentive timers, counters, and flag registers remain unchanged; but the contents of non-retentive timers, counters, and flag registers are cleared.

Cold start: When the PLC-CPU restarts, before executing the main loop OB1, the organization block OB102 is processed first. At startup, the contents of all PLC data blocks (DB) are cleared, and the original set values ​​are re-entered from the load memory; the contents of all CPU timers, counters, and flag registers are cleared (regardless of the retention area and non-retention area).