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)
// Read next 4 bytes of user data
// Read next 4 bytes of user data
// Read next 4 bytes of user data
// Read next 4 bytes of user data
// Read next 4 bytes of user data
// Read second last 2 bytes of user data
// Read last byte of user data
// Acknowledge with no. of data packet
// Send as acknowledgment to optical reader
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.