Chapter 1. Introduction
12
PACSystems RX3i Genius Communications Gateway
GFK-2892F
IO Scanning
In the PACSystems RX3i PROFINET network, multiple IO cycles run asynchronously and independently. Figure 7
illustrates typical cycles in a system with an RX3i CPU with a PROFINET Controller module communicating with
a Genius Communications Gateway. Cycles may be different for third-party devices.
Genius
I/ O
Genius
I/ O
Genius
I/ O
Genius
I/ O
Genius
I/ O
PROFINET I/O
Genius
I/ O
Genius
I/ O
Genius
I/O
Genius
I/O
Genius
I/O
Genius Bus Scans
P
S
C
P
U
P
N
C
PROFINET IO
Production Cycle
RX3i CPU Sweep
Figure 7: PLC - GCG - Genius Scan Cycles
Genius IO-Device Scan
: In this example, each GCG scans all of its Genius devices. The GCG stores the devices’
input data into its internal memory. Every time the GCG gets a turn on the Genius bus, it transmits the output
data from its internal memory to each of the Genius devices.
3
rd
party devices:
The transfer of IO data between an IO module and the PROFINET IO network is device
dependent. Refer to the third-party manufacturer documentation for specifics for a particular device.
PROFINET IO Production Cycle
: Each PROFINET Controller and IO-Device publishes data from its internal
memory onto the network at its scheduled PROFINET production cycle (Note: Production cycles between
IO-Controllers and IO-Devices are not synchronized; each publishes at its configured update rate
independently). The PROFINET Controller publishes output data received from the RX3i CPU to each IO-Device,
and the IO-Device publishes input data from its memory to the PROFINET Controller.
RX3i CPU Sweep
: The RX3i CPU Sweep includes both an input scan and an output scan. The CPU input scan
retrieves the current input data being stored within the PROFINET Controller module. This input data is then
available for use by the application logic. After the logic solution, the CPU output scan writes the outputs to the
PROFINET Controller.
