7.5 MRP
To increase the network availability of an industrial Ethernet network, you can connect a
line topology
together to a
ring topology
. To set up a ring topology with media redun-
dancy, you have to bring together the two free ends of a linear bus topology in one
device. Closing the linear bus topology to form a ring is achieved with two ports (ring
ports) of a device in the ring. At least one device of the ring takes the role of the
redun-
dancy manager
. All other devices in the ring are
redundancy clients
. A standard media
redundancy method is MRP (Media Redundancy Protocol). Up to 50 devices per ring can
participate. The MRP (
M
edia
R
edundancy
P
rotocol) is specified in the standard IEC
61158 Type 10 "PROFINET".
Precondition
n
The ring in which you want to use MRP may consist only of devices that support this
function.
n
"MRP" must be activated for all devices in the ring.
n
All devices must be connected via their ring ports.
n
The ring may contain max. 50 devices.
n
The connection setting (transmission medium/duplex) must be set to "full duplex" and
at least 100Mbit/s for all ring ports. Otherwise there may be a loss of data traffic.
n
The data paths between the individual devices are automatically reconfigured if the
ring is interrupted at any point. After reconfiguration, the devices are accessible
again.
n
In the redundancy manager, one of the both ring ports are blocked for uninterrupted
network operation for normal communication so that no data telegrams are circulated.
In terms of data transmission, the ring topology is a linear bus topology.
n
The
redundancy manager
monitors the ring for interruptions. For this he sends test
frames from both ring port 1 and ring port 2. The test frames run through the ring in
both directions until they arrive at the other ring port of the redundancy manager.
n
As soon as the interruption is removed, the original transmission paths are restored,
the two ring ports of the redundancy manager are disconnected and the redundancy
clients informed of the change. The redundancy clients then use the new paths to the
other devices.
The time between the ring interruption and restoration of a functional linear topology is
known as the
reconfiguration time
. At
MRP
the
reconfiguration time
is typically 200ms.
MRP is only supported as
redundancy client
. If the ring is opened or closed, you will be
informed via the OB 82 "Neighbourhood change". With SFB 54 you can get more infor-
mation.
The use of MRP in the operating mode I-Device is not permissible and is
rejected during the configuration!
Overview
Function
Reconfiguration time
VIPA PROFINET CP as
redundancy client
VIPA System MICRO
Deployment PG/OP communication - PROFINET
MRP
HB400 | CPU | M13-CCF0000 | en | 18-50
193
