Siemens SIMOCODE pro Function Manual page 158

Tables, data records
3.3 Tables, PROFIBUS data records
Writing / reading data records with STEP7
You can access the data records from the user program.
● Writing data records:
– S7-DPV1 master: by calling SFB 53 "WR_REC" or SFC 58
– S7 master: by calling SFC58
● Reading data sets:
– S7-DPV1 master: by calling SFB 52 "RD_REC" or SFC 59
– S7 master: by calling SFC 59
Further information
You will find further information about the SFBs:
● in Reference Manual System software for the S7-300/400, system and standard functions
(https://support.automation.siemens.com/WW/view/en/44240604)
● In the STEP7 online help
Byte arrangements
When data longer than one byte is stored, the bytes are arranged as follows ("big endian"):
Figure 3-2
Abbreviations
See SIMOCODE pro – System Manual
(https://support.industry.siemens.com/cs/ww/en/view/109743957).
158
Byte arrangement in "big endian" format
SIMOCODE pro - Communication
Function Manual, 11/2018, A5E40508495002A/RS-AC/003