Does anyone know or have heard if GE is planning to replace the Mark VIe? Will there be a Mark VII or a new DCS? Timeline?
Excellent question, and one which was recently asked here on control.com. No one really knew when the next version of turbine control was scheduled for release. But, based on GE's recent actions in the turbine control arena, it's probably a safe bet they are developing the "Mark VII" as we write this, and will "obsolete" the Mark VIe in 12-15 years after the release of the "Mark VII." It's understandable why the Mark IV and Mark V were obsoleted, but the Mark VI is not so understandable--not from a hardware perspective, anyway. Most of this "obsolescence" is likely done to try to sell new turbine control systems, and to make it "easier" for GE to drop support for older hardware.
It's a valid concern--especially if you're considering a Mark VIe system in the near future. I will say this, though--I do believe that GE, at least based on their recent product offerings--has finally started to realize that the turbine and auxiliary equipment outlive the control systems and they are trying to think about future upgrade paths and making them easier than they have in the past when they've completely redesigned the control system hardware. That's a personal observation, not based on any facts--just observations, and a fervent hope that upgrade paths are indeed being strongly considered for future product lines/enhancements. So, if you bought a Mark VIe today, and the Mark VII came out in 2018, it's certainly possible that there would be an upgrade path to the Mark VII which would make it easier and simpler than it has been in the past.
As for timeline, based on past product lines and how long the Mark VIe has been in production it's probably sooner rather than later.
There is one big caveat in all of this. The division of GE that designed turbine control systems is no longer a part of the division that designs and builds turbines. It is now part of a different division of GE, and the leader of that division is a HUGE proponent of PLCs (Programmable Logic Controllers)/PAC (Programmable Automation Controllers). And, the turbine products division is a part of the programmable controller division....
So, all of the above may be just wishful thinking. And none of us is going to know until it's underway.
Best of luck!