Siemens SIMATIC S5 Manual page 118

Byte 28 Main control byte 2
Bit 7: This function applies for all controllers, for which self-tuning is possible (even if it
is not activated), when main control byte 1, bit 2 = "1" and for all controllers where
a self-tuning function was run successfully, when main control byte 1, bit 2 = "0".
Bit 7 can be transferred to the IP with the FB 162 commands "KS", "PA" or "AE
message 15":
If bit 7 = 1, bit 1 of the error bytes 0a to 12a is not set.
IP244
C79000–B8576–C860–02
Data Exchange with the Central Controller
4–51