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Chapter 6 . COMMREQ/Data_Init_Comm Programming
4) Check the status of the initiated COMMREQ task . COMMREQs should be executed
sequentially. The application program should check that the status of the previous
COMMREQ to the targeted PROFINET Controller is complete before sending it another one.
Failure to do this may result in improper operation of the PROFINET Controller.
6.3 COMMREQ Command Block Format
The first step in programming communications requests is to set up the contents of the
COMMREQ instruction. This can be done using Block Moves or similar program instructions, as
shown later in this chapter.
CPU Memory Application Program
Command Block
⇐
Edit content of COMMREQ
Data is placed in adjacent locations in CPU memory to form a Command Block, per the format
shown below:
Location Data Field Value
address “Data Block” Length
a 1 Wait/No Wait Flag Always 0
a 2 Status Pointer Memory Type
a 3 Status Pointer Offset
a 4 Idle Timeout Value (ms) Always 0
a 5 Max. Communication Time (ms) Always 0
a 6 to
a 78
Data Block
The length of the Command Block depends on the type of COMMREQ being sent. Seventy
words is the maximum and is used only for a COMMREQ that transfers a 128–byte datagram.
Most Command Blocks are much shorter. The table in Section 6.3.3 gives an overview of the
contents of each type of COMMREQ that may be sent to a PROFINET Controller for transfer to
a Genius Gateway.
46 Public PACSystems RX3i Genius Communications Gateway User Manual GFK-2892B