Chapter 1
.
Introduction
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.
14
Public
PACSystems RX3i Genius Communications Gateway User Manual
GFK-2892B
