Crosses appearing on graphics
There are 15 wellheads connected to our system and two more wellheads added to the same 800XA system from another location. Problem is crosses are appearing and clearing itself frequently on four out of 15 wellheads graphics (including the two wellheads on seperate location). MMS comms failure alarm is appearing and clearing itself for one of the wellhead of two. OPC is seen connected for all the wellheads (OPC DA & OPC A&E). All wellheads are connected to redundant connectivity servers. The problem was rectified by restarting the servers. Question is why crosses are appearing only on particular wellhead graphics even though OPC is showing healthy. Same time MMS comms failure alarm generates on two wellheads.
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Theres a bunch of potential reasons for this, but since you're seeing MMS comms errors, this tends to suggest issues with the comms network rather than 800xA services problems ... The OPC uses MMS to communicate to the controllers, but MMS is a controller peer-to-peer comm protocol and is completely separate from the 800xA HMI parts. So even if 800xA services fail, the MMS comms should be unaffected.
With the info you've given, there's no definitive answer we can give you. You will need to start gathering a lot more information about things like ...
When did the problem start ?
Where could the problem be ?
Where could the problem NOT be ?
What diagnostic tests can you run to prove / disprove causes ?
This may happen when multiple engineering stations at the different control rooms conencted to the Control networks so always OPC clients looking for the near by one so there are chances of getting frequent crosses on the operator graphics,so please disconnect the control network cables from all the engineering stations & ensure all engineering stations are connected to only client server network & make the connectivity server as the router to do the engineering activities.
Please share your system configuration drawing.
There are 15 wellheads named wellhead 1 to wellhead 13 on one location similarly wellhead 14 & wellhead 15 on another location. Wellhead 15 MMS Comms failure alarm was reported. Soon after crosses appeared on the graphics of each wellhead. To see if the OPC connectivity is ok OPC was seen for (DA) & (A&E). But surprisingly all of them were healthy (both OPCs each on CS1 & CS2). Anyhow, CS1 was restared and CS2 came to backup. Crosses from all wellheads were gone except for (wellheads 8/13 & wellhead 14/15). At the same time MMS comms failure alarm was appearing and clearing for wellhead 15 and wellhead 9. Hence, both servers were restarted one by one. The crosses and red diagnol line appears and disappears on wellheads 8/13 & wellhead 14/15 and same time MMS comms failure alarm just for 15. The problem was normalised with time in the evening. Everything was fine whole night but again in the morning probably the same time it started again. Crosses appearing on wellheads 8/13 & wellhead 14/1. MMS comms failure alarm for wellhead-15 , 9 and 10 were seen and clearing.At the same time controllers for various wellheads were seen to shift from remote to local and vice versa themselves. When these wellheads are "pinged" ping times out several times and connects and then times out after several good connections. All these wellheads are connected via fiber link. Can fiber losses lead to such situations (Fiber has primary and secondary links in form of contra-rotating ring). What could be the possible reasons ?
For reference the alarm first appeared is attached. Alarm for wellhead 8 also appeared then MMS for WH 15