User Documentation

User Manual Managed Switches

147

The PROFINET I/O connection can be configured for both cyclic I/O data and I/O parameters. I/O

parameters are acyclic I/O data. These are major setup and monitor attributes in PROFINET.

Cyclic I/O Data

Cyclic I/O data are always sent between the PLC and Switches at the specified periodic time. These

data are transmitted almost real time. For example, status information from the Switches, and

variables to be written to the Switch would typically be part of the cyclic data.

I/O Parameters

PROFINET I/O parameters are defined for device configuration and status monitoring. These data

are useful for infrequent data transfers, or for very large data transfers. Only transfer when needed

Alarm

Alarms are mainly PROFINET I/O transmitted high-priority events. Alarm data are exchanged

between an I/O device and an I/O controller. Once an event triggers it, the switch will send the alarm

to the PLC immediately. Enable or disable these alarms by setting I/O parameters.

PROFINET Cyclic I/O Data

The Weidmüller switch provides PROFINET I/O cyclic data as described in below table.

NOTE: The default transfer frequency of the Switch’s PROFINET Cyclic I/O data is 128 ms. There

are 3 options available in SIMATIC STEP 7: 128 / 256 / 512 ms.

PROFINET Cyclic I/O Data Table