Siemens SIMATIC MV500, Operating Instructions Manual, Page: 182 / 294

Process interfacing via an automation system (PLC, PC)
9.4 Control with FB 79
SIMATIC MV500
182
Operating Instructions, 03/2021, C79000-G8976-C494-05
//Enter data ID (in principle only necessary in the first cycle)
T DB17.DBD 4 // Store in DB
L ED 13 // Read next 4 bytes of user data
T DB17.DBD 8 // Store in DB
L ED 17 // Read next 4 bytes of user data
T DB17.DBD 12 // Store in DB
L ED 21 // Read next 4 bytes of user data
T DB17.DBD 16 // Store in DB
L ED 25 // Read next 4 bytes of user data
T DB17.DBD 20 // Store in DB
L ED 29 // Read next 4 bytes of user data
T DB17.DBD 24 // Store in DB
L EW 33 // Read second last 2 bytes of user data
T DB17.DBW 28 // Store in DB
L EB 35 // Read last byte of user data
T DB17.DBB 30 / // Store in DB
// Acknowledge with no. of data packet
m001: L EB 5 // Number of data packet
T AB 5 // Send as acknowledgment to optical reader
BEA
9.4.4 Programming data fragmentation
Handshaking
The following sections introduce a handshaking procedure that ensures the consistency of all
the data transferred from the optical reader to the I/O controller regardless of any configured
consistency mechanisms in PROFINET. This procedure must be used with every data transfer,
even if the transfer only consists of one data block, for example when reading out the
program number selected on the optical reader.