lvdt # 2 rms voltage for monitor 2 out of limit ???


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WHAT DEVICES ARE THE LVDTS INSTALLED ON? (In other words--what device is being driven by Regulators 1 and 2 (a fuel control valve, or a steam control valve, or ???))
I just want to note that many times the quality of the responses received are directly related to the quality of the information provided.
It's a very long time since I coded software with probably one of the first lvdt's made - that couldn't go out of limits so the above message seems to be a cryptic code:
a) lvdt is broken
b) time to panic !

Clearly someone has realised this is off a turbine;
in which case could you explain what an rms voltage is in what I would have thought is a DC supplied control system.

The Mark VIe is can use just about any power source--from 12- or 24 VDC to 220 VAC. (The "preferred" (preferred by the division of GE that designed and built the Speedtronic Mark* series of controls, including the Mark VIe) power supply is 125 VDC--because that what GE has for decades used for the emergency Lube Oil pump power source and it just made sense to use it for the turbine control system also.) That's because the incoming ("mains") power is connected to power supplies that convert the incoming power to 28 VDC (don't ask!) for distribution and use throughout the Mark VIe, for I/O Packs, for processor power supplies--just about everything.

In the case of LVDTs the I/O Packs receive the 28 VDC power and then they develop 7.00 VAC RMS to power ("excite") the LVDTs, and those same I/O Packs also receive the differential voltage output from the LVDTs and convert that signal into position (usually in percent of travel, or degrees angle). (In the case of things like two-, three- or four-wire transmitters, the I/O Packs develop 24 VDC (sort of; since most transmitters have an input voltage range and 28 VDC falls neatly into that range) that is then applied to the transmitters. Most of the other analog I/O (Inputs/Outputs) typically used with GE-design turbine controls are self-powered, such as T/Cs, and passive speed pick-ups, and velocity ("seismic") vibration pick-ups. The Bently-Nevada proximitors and other accelerometers can be powered by the I/O Packs required for their use.)

So, it's kind of likely that the I/O Pack mentioned in the Diagnostic Alarm messages (PSVO, for Pack-Servo-Valve Output) is probably experiencing some kind of issue, or the interconnecting wiring between the I/O Pack and the LVDT, or the LVDT itself is bad.

The Mark VIe System Guide, GEH-6721, has sections for every I/O Pack and the Diagnostic Alarms for each I/O Pack are "described" there, along with some very brief troubleshooting information (I wouldn't necessarily call it troubleshooting "help"--but it's better than nothing if one has little or no familiarity or experience with the Mark VIe). There are some versions of the System Guide which have a dedicated volume (Vol. III, usually, I believe) that is ONLY for Diagnostic Alarms (there are SO MANY of them--but the troubleshooting information is still minimal and cryptic at best).

AND, some newer versions of ToolboxST (the application/program that is used to configure and troubleshoot and maintain the Mark VIe) have the ability to display the same information available in the System Guide by double-clicking on the Diagnostic Alarm message or Drop Number, though many people don't know about or use that ability--but, the information provided is exactly the same as what's available in the System Guide.

I understand English is not every original poster's native language, but in today's digital world one can either use a language translator application on their smart phone or on the World Wide Web to type in their question in their native language and receive and English translation which can then be copied and pasted into, OR, they can (and a very few have) type their question in their native language and readers can then translate it. That does have its problems--most translator programs aren't very good at technical terms and words. But, we gotta have some information--some context--for problems like this. This IS a technical forum--and we can't telepathically or intuitively understand every issue. And, people have to understand at some point that just like all Mercedes-Benz vehicles are not the same just because they have the Mercedes-Benz badge on them, that all GE-design Frame n heavy duty gas turbines are not the same and all Mark VIe's are not the same. The Mark VIe can be configured for all types of I/O, for all types of turbines and applications. That requires different I/O Packs and I/O terminal boards, and it requires assigning I/O to input/ouput channels--they're not all the same and most I/O Packs can handle a number of inputs or outputs (such as 12 or 24 discret inputs, or 4 or 6 or 8 LVDTs (or more in one case)). Simply posting a photo of a list of Diagnostic Alarms and basically repeating that information in the Subject of the thread isn't enough information. (At least not for me. And, I am increasingly annoyed at the number of people who think they can just write "GE Frame 9E or Frame n" and think that's all they need to provide because their problem is generic and someone will just immediately know what the solution is. And, it's up to me to decide what to do about that--and it's increasingly looking like leaving the forum is the only way to eliminate the annoyance. That, or just don't respond unless good information is provided by the original poster....)