Secondary Connection to Controller Lost Error keep coming
We are facing an issue with our PM891 redundant controller. Controller was running without any issue for the past 6 months, suddenly we are finding an System Alarm "Secondary connection to PMS lost". PMS is my controller name. when we checked the Ethernet port configuration, we found error 16#50020000. with description as "Port Disabled, Network Storm detected". Can you help with the solution for the same as I have a doubt regarding the description of this alarm given in help of control builder. It says "CEX bus fuse blown or missing". I am a little confused as some people told me its is because of Network loop from RNRP. For the information, we were trying to achieve the profibus redundancy at the media converter level. After that this problem has been observed.
What is the content of the controller log?
Since firmware 5.1.1-3, a storm reported by AC 800M should mean the maximum permissible number of packets per second has been exceeded. The storm protection only make temporary block, then releases it, to block again if the storm continues.
PM891 trigger storm at 1600 Ethernet packets per second.
In firmware prior to 5.1.1-3, RNRP loop protection may trigger loop (because of storm) and if subject to "dual storm" (on both Ethernet intefaces) keep one interface permanently blocked. RNRP loop protection was changed to loop detection in 5.1.1-3, only report, take no action.
If you have 5.1.1-2 or older, you should be able to open the blocked port by performing a dummy change of a RNRP parameter, e.g. Max Number Of Remote Areas. Download a new value (+1), then download the original value again. Download from local CBM on same subnetwork. Do NOT download from a remote network, e.g. client/server network. Routed download may stop half way (due to RNRP restarting and dropping the routed access for a short period). If download become interrupted, controller reset is often required.
Do not mix up these three:
- AC 800M Storm Protection
- RNRP Loop Detection
- RNRP Loop Protection
There is a Technical Description on ABB Library detailing the System 800xA protection mechanisms preventing flooding of Ethernet interfaces.
CEX-bus fuse blown is a hardware error requiring repair in workshop (IIRC), I believe its unrelated to the storm.
- _General warning;
- CEX-bus fuse;
So it looks lijke you have mutiple problems:
- The network port being blocked;
- the cex-bus fuse blown;
- On the power connector feedback from the second power supply is missing.
Do you have only primary control network (CN1) cable connected for the PMS controller, but actually have redundant network cables connected for other controllers and nodes?
Actually, the reported system alarm: 'Secondary Connection to xxx lost' is an alarm generated by the PPA System Status function that does not know if the connection is redundant or not.
Make sure you either have all the controller and nodes with non-redundant NICs or with redundant NICs, but not mixture of both. You can check the LAN cable connected to PMS or try replacing the cable. If required, you can Filter these alarms.