I'm about to integrate logic modifications and hmi updates to a GE Mark VI system at a CCGT plant. I've done similar work on other dcs's, but this is my first time on the Mark VI. anything I should be wary of? appreciate any input!
if you know how to do it, it should be quite straightforward. This is what I normally do, specially when I am in a site I have no previous experience with (but not only then):
1. Make sure the m6b file you will work with is the version that runs on the MarkVI panel. This is easy, just open the file in Toolbox, go on-line and make sure it spells "Equal" in the right-bottom corner of the Toolbox window (green highlighting). If it says "Minor difference" in yellow or "Major Difference" in red, then you have the wrong one.
2. Make backups of the m6b file, hmb file and HMI screens.
3. Make sure there are no Control Constants that are "forced" but not changed in the software itself. It happens sometimes that people change control constants during operation (alarm limits, for example) without modifying them in the software and performing a download. For this, while on-line, go to View, Control Constants and you can see on a column the actual value and on the next one the software value of the Control Constants. Go through the whole list and make sure there are no differences between the two columns.
You will, most probably, find some that are different not because they were "forced", but because the software itself changes them during operation. Not all Control Constants are really constant. Just trace in the software those that are not equal (actual and software values) and, if they are an output of a software block, then there is no problem.
If you find Control Constants that have been "forced", find out why and, if acceptable (sometimes operators have crazy ideas and make crazy and dangerous choices), change them in the software as well to have a clean configuration.
4. Follow your modification procedure. In the end, make sure to save the m6b file with clear revision explanation.
