1. R0 vcmi did not receive data from r1 or r8 from Dec. 8 to recently. However, suddenly it cleared and T0 vcmi does not see data from S0.

2. R1 processor annunciated many IO alarms.

GE tried to solve this problem without unit trip, but failed.
So GE recommended that vcmi should be replaced after unit trip even unknowing exact cause.

Who can let me know probable cause and how to replace without unit trip and risk?

Good advice should be very useful for me.

 

hi

to replace VCMI you have to power down the rack, (just the rack containing the failed VCMI) and replace the card, power on the rack, and in tool box choose the VCMI card replaced and make DOWNLOAD.

 

Dear Lee YJ,

first off it would be helpful if you provide more information as the the turbine or system being controlled by the MKVI.

That being said here are my comments.

The MKVI TMR unit for controlling most turbines is designed and touted as being able to lose one controller core and continue to run without tripping. In the reality that I have been part of, this is not always the case.

There are many features of wiring and programming that must be correct for a MKVI TMR to operate properly on loss of a single controlling core. The different versions of Toolbox software and its firmware for each particular card have changed through the years as well, which makes the MKVI better able to handle the loss of a core and not trip.

To really be confident that a particular unit will continue to run with the loss of a core, I suggest testing this function during commissioning by doing just that. Making sure that there are NO diagnostic or process alarms, shut off one core, with the unit online and verify the unit continues to run. Once complete with that core, restart the core and allow it to reach control and synchronize with the others. Then clear all alarms with a diagnostic and master reset and proceed to the next. You must understand that the unit may trip during this test. If anything does not operate as intended you must diagnose and figure out the issue before proceeding.

In your case it sounds like you had a possible failure of the VCMI for "R" core? Although I am not clear what you are calling R0 and R1? Also not clear how this cleared, and then "T" core could not see data from "S"?

You need to provide more information as the exact sequence of alarms and failures. What diagnostic alarms were present when the problem occurred? These alarms do not usually clear by themselves, so I not clear when said they cleared then "T" could not get data from "S". Please add more information as to what happened during this event.

I will say that the VCMI is obviously a very critical card, and not just a simple plug and play card in my experience. I personally would not suggest replacing one of these cards with a unit online.