VCMI Loss of Communication on Mark 6

D

Thread Starter

DAMENE

On 2 times I had this problem:

On GT GE Frame 3, equipped with Mark 6 Simplex with VPRO X Y Z.

The First time:

We had a loss of communication between VPRO X and HMI and UCVE.

I tried to solve this probleme by replacing the VCMI H2B by the VCMI H2C using a CD and procedure.

The problem with VCMI H2B no possible communication. After replacing the New VCMI H2C, the communication is normal.

I left the site and come back to my office. After 1 week..........The same problem, Loss of communication.

Before to try to find the solution for this problem, I saw more posts on control.com. maybe i could find help. yes it was helpful.

Then I come back to site and try to see what happen this second time.

Loss of communication and the STATUS LED on VCMI is orange.

I reboot the Controller R and VPRO. the communication is normal. but when I tried to communicate with VPRO X, it is impossible to do it.

I thought to replace the VPRO X by a new one.......

The end idea coming in my mind is to remove the VPRO X. that what I did. I remove the VPRO X, check it, and then install it.................. just this.

Remove it and reinstall it.

After that I powered all VPRO X Y Z and Controller UCVE. The communication is normal with all cards: UCVE, VPRO X Y Z.

Since this day it was ok.

Really what happens inside the system, I do not know.

Thanks for any answers
 
Damene,

In my personal experience, I have seen far too many sites use high-powered radios in the control compartment/room where the Mark VI is located, sometimes with the Mark VI control panel doors open--even just slightly.

Combine this with the fact that proper earthing/grounding practices were often not followed, particularly when older control systems were upgraded to Mark VI control systems, and this is a recipe for all kinds of Diagnostic Alarms and intermittent problems.

There is also the capacitive effect of improper earthing/grounding of some conductors and control system components which can cause some unusual and intermittent problems.

Some atmospheres have some corrosive gases present which can corrode conductors making for poor contact over time--and simply unseating and reseating them once can alleviate the problem. In such environments it's necessary to use conductive grease--too much can be just as bad as too little!--to protect contacts from corrosion. And, the grease should be wiped off and re-applied periodically--and most sites do very little housekeeping in the control compartment/room where the Speedtronic turbine control system is located.

And, contrary to popular belief air conditioning is provided in control compartments/control rooms where control systems are located <i>primarily for humidity control,</i> not for human comfort. Yes; control systems generate heat and need to be cooled, but too much cooling in a humid environment can cause moisture condensation on control system components. Combine that with dust and you've got a perfect recipe for trouble--intermittent, nuisance problems.

And, too much heat can also cause the Mark VI to behave poorly.

You haven't told us about the housekeeping conditions in the areas where the Mark VI is located, or the air conditioning maintenance. We don't know what kind of gases may be present in the atmosphere at the plants where these units are located. And, we don't know if someone has confirmed proper earthing/grounding. And, since you're not on site--can you absolutely, with certainty trust that the site personnel don't stand in front of the panel with the doors open and transmit on their radios? Or, just stand in the area where the Mark VI is and transmit (since it's usually cool)?

Hopefully, MIKEVI can provide some more info; he has a good deal of experience with Mark VI.
 
Dear Damene,

From your post I am not completely sure I understand the problem you encountered. but I will attempt to explain MKVI operation as I understand it, and suggest some things that you can check.

In your case you have a MKVI simplex rack using a single MKVI "core" and 3 VPRO's. In the MKVI rack you will have a single VCMI(Bus Communication Master) card in the left most slot. Next to it will be the UCVE (Processor), and then whatever cards are needed for your application will be placed in the slots to the right of the UCVE.

The purpose of the VCMI card is to communicate with the UCVE and other rack mounted cards via the MKVI backplane, and the VPRO cards via the COAX called the "IONET". The VCMI does not talk to the HMI. Also the UCVE does not talk to other cards in the rack. The VCMI talks to all I/O cards in the rack via the backplane and sends this information to the UCVE. And the VPRO cards to do not talk directly to the UCVE but must use the VCMI to translate.

The purpose of the UCVE processor card is to run the application code, collect information from all I/O through the VCMI, and issue commands that are then sent to the VCMI and then to all I/O cards. The UCVE also communicates with the HMI via Ethernet for the Toolbox and Cimplicity applications.

You did not provide much information as to what exactly was happening when "We had a loss of communication between VPRO X and HMI and
UCVE." IF the VCMI failed then you would have lots of diagnostics and trip if the unit was running. But because the UCVE communicates with Toolbox and Cimplicity then you should still have values displayed on the HMI(it should not be all black). Listing the diagnostics you encountered from the UCVE, VCMI, and VPRO's would help me better understand and guess what may have occurred.

I will say that there was a TIL(Technical Information Letter) issued in September of 2013, TIL-1905 that discusses a potential issue with VCMI or VPRO cards and an intermittent loss of communications.

Mark VI IS215VCMIH1B, IS215VCMIH1C, IS215VCMIH2B, IS215VCMIH2C and IS215VPROH2B boards manufactured between May 2006 and February 2009.
Mark VI control system uses the VCMI board for communication and the VPRO board for protection. The VCMI board in the control and interface module communicates internally to the I/O boards in its rack, and to the other VCMI & VPRO boards through the IONet. The Turbine Protection Module (VPRO) and associated terminal boards (TPRO and TREG) provide an independent emergency over speed protection for turbines. IONet is an Ethernet 10Base2 network used to
communicate data between the VCMI communication board in the control module, the I/O boards, and the three independent sections of the Protection Module <P>. Each VCMI and VPRO uses a transceiver chip which controls communication signals through a single IONet.

Recently a site had several diagnostic alarms related to intermittent and persistent communication issues with specific
VCMI, VPRO and UCVx boards. Refer to Appendix I for details of the diagnostic alarms. After investigation it was found
that these alarms were caused due to problems with socketed IONet transceiver chips on VCMI and VPRO boards.
Transceiver chips are placed on VCMI and VPRO boards either in a socketed chip carrier or can be directly soldered to
the board. Socketed chip carriers were used on IO boards manufactured between May 2006 and February 2009. In some cases, oxidation between the chip and the socket increases the resistance, resulting in communication failure on the associated IONet with other VCMI and/or VPRO boards.

I would suggest you obtain a copy of this TIL from your GE contact as it shows where the chip is located and how to identify if your cards are using chips that are "soldered" or "socketed". I hope this helps, please write back and let us know how you proceed.
 
Dear CSA,

Thanks for your answer, I will try to answer to your post step by step.

Yes, we have a high-powered radios in the control room installed at 5 meters to the Mark VI panel, and really sometimes the Mark VI control panel doors are open, but just for maintenance.

Yes, the Mark 2 control systems were upgraded to Mark 6, at the same Older control room.

The housekeeping conditions in the areas where the Mark VI is located, are normal not hot not cold. No gases are present in the atmosphere.

The earthing/grounding are too normal.

I am sure, since I am not on site the personnel don't stand in front of the panel with the doors open. The doors are open just if there is a problem.

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Dear MIKEVI,

Thanks more for your answer. your explanation is very easy to understand.

Yes, we have a MKVI simplex rack using a single MKVI "core" and 3 VPRO's. The MKVI rack have a single VCMI ; UCVE and others cards I/O (21 cards totally).

When I tried to communicate from HMI to VPRO X using toolbox, We had this message:

ADL message time out from HOST CRM3_SVR to hot 192.168.101.141

This explain that we cannot establish a communication between VPRO X and HMI.

When we had this loss of communication the GT are not running. But we knew that if the GT was running we would get a trip.

I will try to search this TIL issued in September of 2013, TIL-1905.
 
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