Siemens SIMATIC S5 Manual page 120

Byte 30 Main control byte 4
Main control byte 4
Bit 0 Start bit for measured value acquisition on channel 13. Acknowledgement is by
clearing bit 2
Bit 1 Causes a cold restart. This clears certain memory areas in the IP
(e.g. "integrator values or self-tuned values") (see command "KS": FB 162).
This bit must be set when:
a) the PLC is switched on for the very first time;
b) the PLC has detected a battery power failure while the power supply was off
(with S5-115U/135U).
In addition to this, the whole IP is re-initialized according to the values in messages
0 to 15 and 30 to 42.
The bit is reset by the IP.
IP244
C79000–B8576–C860–02
Data Exchange with the Central Controller
2
in status byte 1, message 16 (see Direct Functions: FB 162).
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