Network Loops on PM866 Ac800M controller
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Hello, can u please explain ur system config?how u have designed means both control network and plant network are in same area of rnrp or you have considered separate network or area for plant network(generally area 1(1*4 )means 172.16.4.x) and separate network for control network(162.16.80.x) area 20(4*20).
So if control network is deffrent then ur control network primary r secondary may be looped to make a ring without using any settings in switches to use ring toplology. So remove the loop between end switch and starting switch and then clear the buffers using the rnrp tracer using option 4 and then run the tracer to check the loop.
If its plant network and control network are common then remove the loop between end switch and starting switch perform in both primary network as well as in secondary network
Answers
You first have to see if it's an old message or a new.
To find out if problem is ongoing or not, use the RNRP Utility to clear the error logs in all nodes and perform a new check some time later. To easily reset all logs on e.g. RNRP area 20 in one operation; use this trick in the RNRP Utility on one of the PCs with physical connection to area 20:
Tools to help find problems in network configuration, ver 4.0, src_port=2424
------------------------------------------------------------------------
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0 - Quit
1 - Search own networks for nodes with configuration or network errors
2 - Get configuration parameters and error logs from one node
3 - Get network map from one node
4 - Change log conditions in one node (for experts)
5 - Test rnrp response time from one node
6 - Find nodes with rnrp on one network
7 - Unblock interface blocked in Windows after network loop detection
8 - Network to node throughput test. Caution, this may disturbe node !!!
Enter your choice : 4
Enter node IP-addr : 239.239.239.80
Select:
0 - Return
5 - Enable trace logs from area routing
6 - Disable trace logs from area routing
7 - Enable trace logs from network interface
8 - Disable trace logs from network interface
11 - Clear log buffers
Enter your choice : 11
"239.239.239.80" is the multicast address used by RNRP on network area 20 and will have all nodes to execute the clear log buffers command in parallel. The figure "80" is derived from RNRP Area number x 4.
After some time run the error search again and see if you still have a problem.
Check your network since loops can not emerge from an AC 800M CPU itself.
In some network topologies like redundant rings or spanning trees loops are a natural thing that occur every time an open path is closed, but the loop should not exist for longer than a second.
Default STP/RSTP *SELDOMLY* fulfill this requirement and the loop may exist so long that a controller may intentionally stop (most ABB controllers are designed this way). Hence, ABB does not recommend spanning trees on control networks.
Proprietary ring protocols like Westermo's FRNT or Hirschmann's HiPer Ring will resolve the loop in a fraction of a second. Still hundreds or thousands of looped packets may be slip through before the loop is resolved by the ring management protocol.
RNRP will detect a loop if just 7 packets with the same sequence number is received within the same second.
Hence, closing a ring or an open path in a properly configured spanning tree often result in a few loop detections.
Retrieve the controller logs and check how long the loop existed. A controller with redundant network will make one short blocking and then close the affected port for an hour (60 minutes) if the loop persisted over the short block:
E 2014-05-27 11:29:02.121 RNRP Config error: Suspected network loop, short interface block made on area=20 path=0
E 2014-05-27 11:29:07.474 RNRP Config error: Interface unblocked on area=20
E 2014-05-27 11:29:07.577 RNRP Config error: Interface blocked after detected network loop on area=20 path=0!!
E 2014-05-27 12:29:08.662 RNRP Config error: Interface unblocked on area=20 path=0,
A controller with singular network connection will only perform short blockings on the only available port and check loop status roughly every 7th second.
E 2014-05-27 11:29:09.914 RNRP Config error: Suspected network loop, short interface block made on area=20 path=0
E 2014-05-27 11:29:17.474 RNRP Config error: Interface unblocked on area=20 path=0,
E 2014-05-27 11:29:21.215 RNRP Config error: Suspected network loop, short interface block made on area=20 path=0
E 2014-05-27 11:29:28.967 RNRP Config error: Interface unblocked on area=20 path=0,
E 2014-05-27 11:29:32.252 RNRP Config error: Suspected network loop, short interface block made on area=20 path=0
E 2014-05-27 11:29:39.968 RNRP Config error: Interface unblocked on area=20 path=0,
E 2014-05-27 11:29:43.260 RNRP Config error: Suspected network loop, short interface block made on area=20 path=0
E 2014-05-27 11:29:50.968 RNRP Config error: Interface unblocked on area=20 path=0,
E 2014-05-27 11:29:54.304 RNRP Config error: Suspected network loop, short interface block made on area=20 path=0
If you see two or more such "blockings" you probably have a network problem which may cause potential problems for your controllers.
Check your network for potential misconfiguration!
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