Siemens SINAMICS G120 Operating Instructions Manual page 191

Figure 5-39
Flags 9.0 to 9.3 specify whether parameters are read or written:
● M9.0: request to read parameters
● M9.1: request to write parameters
● M9.2: displays the read process
● M9.3: displays the write process
CU240S and CU240E Control Units, FW 3.2
Operating Instructions, 03/2009, A5E02440075B AA
STEP 7 program example for acyclic communication - OB1
5.11 Operation in fieldbus systems
Functions
191