Rockwell Automation Allen-Bradley 871FM-M10BA30-x, Руководство пользователя, Страница: 19 / 90

Rockwell Automation Publication 871FM-UM002A-EN-P - April 2017 19
871FM Miniature Metal Flat Pack with IO-L
ink
Overview Chapter 3
Access IO-Link Data
Cyclic Data
To exchange the cyclic process data between an IO-Link device and a
controller, the IO-Link data from the IO-Link master is placed on the address
ranges assigned beforehand. The user program on the controller accesses the
process values using these addresses and processes them. The cyclic data
exchange from the controller to the IO-Link device (that is, IO-Link sensor) is
performed in reverse.
Acyclic Data
Acyclic data, such as device parameters or events, are exchanged using a
specified index and subindex range. The controller accesses these using Explicit
Messaging. The use of the index and subindex ranges allows targeted access to
the device data (that is, for reassigning the device or master parameters during
operation).
Start-up the I/O System
If the port of the master is set to IO-Link mode, the IO-Link master attempts
to communicate with the connected IO-Link device. To do so, the IO-Link
master sends a defined signal (wake up pulse) and waits for the IO-Link device
to reply.
The IO-Link master initially attempts to communicate at the highest defined
data transmission rate. If unsuccessful, the IO-Link master then attempts to
communicate at the next lower data transmission rate.
If the master receives a reply, the communication begins. Next, it exchanges the
communication parameters. If necessary, parameters that are saved in the
system are transmitted to the device. Then, the cyclic exchange of the process
data and value status begins.
Assign Device Parameters
Configuration of a device for a specific application requires changes to
parameter settings. The device parameters and setting values are contained in
the IODD of the device.
I/O Device Description (IODD) files contain information about the device
identity, parameters, process data, diagnostic data, and communication
properties. These files are required to establish communication with the
sensors via IO-Link.
The IODD consists of multiple data files; the main file and several optional
language files are in XML-format and graphic files are in PNG format
(portable network graphics). These files adhere to the IO-Link open standard,
which means that they can be used with any IO-Link masters.
IODD files are assigned using Studio 5000® and the 1734-4IOL Add-on
Profile (when using the 1734-4IOL IO-Link master module).