Siemens SIMATIC S7-1500 Manual page 52

Parameter data records
A.2 Parameter data record 1990
Data record structure (read)
Byte
0
1
2 ... 32
The data record "read" remains set to zero until the data record "write" is written.
52
Format Name
uint8 command
uint8 status
uint16 counter
Value
0x42
0 = SUCCESS
1 = ERROR
2 = BUSY (read again)
0 (if status != SUCCESS)
1 ... 9999
Equipment Manual, 07/2023, A5E46384784-AC
Technology Module TM NPU