Manual for MVK-MPNIO Modules
14 V 1.9
2.3 PROFINET Conformance Classes
T
he scope of functions supported by PROFINET IO is clearly divided into conformance classes
(CC). These provide a practical summary of the various minimum properties.
There are three conformance classes that build upon one another and are oriented to typical
applications.
1. S
tructure of conformance classes (ref. PROFINET_system_description)
CC-A provides basic functions for PROFINET IO with RT communication. Cycle time typical
starting at 2ms. Unmanaged Ethernet switches can be used in this class. Wireless communica-
tion is possible only in this class. All MVK MPNIO comply this class. For switches, the
MURRELEKTRONIK unmanaged TREE switches can be used.
CC
-B extends the concept to include network diagnostics via IT mechanisms as well as topolo-
gy information. Cycle time typical starting at 2ms. A simple device swap is possible with the to-
pology information and projected device name. All MVK MPNIO comply with this class.
Murrelektronik TREE Unmanaged switches are transparent for this information. (LLDP proto-
col). But they can not participate to the PROFINET diagnostics and topology information. A
switch can only be included int the topology of the PLC when it is a “PROFINET” managed
switch.
T
he system redundancy function that is important for process automation is contained in an ex-
tended version of CC-B named CC-B(PA).
CC
-C describes the basic functions for devices with hardware-supported bandwidth reservation
and synchronization (IRT communication) and is thus the basis for isochronous applications.
With the implementation of Isochronous Realtime (IRT) for Ethernet controllers, a cycle time of
250µs and a Jitter precision of less than 1µs are normal.
For a real IRT network it is mandatory that all networkelements have an IRT
chipset. If a standard Ethernet chipset is used in an IRT network the IRT
synchronity will be lost.
To Next Page
Loading...