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Chapter 6. COMMREQ/Data_Init_Comm Programming
6.1 COMMREQs and Passwords
Level 1 and 2 controller passwords, which prevent write access, cannot be used in applications that include
COMMREQs. COMMREQs require write access to return their completion status and requested data.
6.2 Programming for a COMMREQ Communication Request
In order to communicate via a COMMREQ with a Genius device attached via a Genius Gateway module, the
application program should perform the following actions.
1) Supply the content of the COMMREQ communication. Ladder logic Block Moves, Data_Init_Comm, or
similar program instructions can be used to place the required information into CPU memory. This content
is called the Command Block.
CPU Memory
Command Block
2) Clear status block. The program should set the status block to all zeroes (see programming example
Figure 30). Establishing this initial condition allows the program to differentiate between the result of an
earlier command and the currently–executing COMMREQ command.
CPU Memory
Status Block
3) Use a COMMREQ instruction to perform the intended function.
Application Program
COMMREQ instruction issued
to targeted PROFINET
Controller
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.
50
PROFINET-Genius
Gateway
converts
COMMREQ
content into
Genius Datagram
PACSystems RX3i Genius Communications Gateway
Application Program
Edit content of COMMREQ
Application Program
Clear status block
(set value to zero)
Genius Device
I/O Module receives Genius
Datagram from Gateway
GFK-2892F
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