Chapter 6
.
COMMREQ/Data_Init_Comm Programming
COMMREQ/Data_Init_Comm Programming
Chapter 6
This chapter explains how to use Communication Requests (COMMREQs) to perform specific
tasks with Genius devices that are attached to a Gateway’s Genius bus. COMMREQs are
instructions in the RX3i ladder logic (see example in Figure 25). When a COMMREQ is executed
in ladder logic, communications traffic is directed to the indicated PROFINET Controller
module (IC695PNC001). The PROFINET Controller then communicates with the Genius
Gateway over PROFINET. The Genius Gateway subsequently sends the corresponding
background datagram to the Genius block Serial Bus Address (SBA) specified in the COMMREQ.
Status, and optionally some data, is returned from the Genius Block via the Genius Gateway to
the PROFINET Controller and then to the reference memory in the CPU module.
Data_Init_Comm is a ladder logic instruction that can be used to help set up a COMMREQ. It is
a more user-friendly instruction from the programmer’s perspective. It performs the same
functions as are described in this Chapter. An example is shown at Figure 26.
For additional information about Genius datagrams, see the
Genius I/O System and
Communications Manual (GEK–90486–1)
, which describes Genius Datagrams in detail.
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
Application Program
Command Block
⇐
Edit content of COMMREQ
2)
Clear status block
. The program should set the status block to all zeroes (see
programming example Figure 25). Establishing this initial condition allows the program to
differentiate between the result of an earlier command and the currently–executing
COMMREQ command.
CPU Memory
Application Program
Status Block
⇐
Clear status block
(set value to zero)
3)
Use a COMMREQ instruction to perform the intended function
.
Application Program
PROFINET-Genius
Genius Device
COMMREQ instruction issued
to targeted PROFINET
Controller
Gateway converts
COMMREQ content into
Genius Datagram
I/O Module receives Genius
Datagram from Gateway
GFK-2892B
PACSystems RX3i Genius Communications Gateway User Manual
Public 45