Hello all.

any one can advice us in our issue pls.

We have GE frame6 gas turbine and uses markv control system with IDOS software. the unit trip because problem happens in two core r&t with this detail:

Core R read A4. after checking I found TCDA card loc1in QD1 power down. and I clean power cable in R core that's supply TCDA then reboot R and goes to A7.

And core T also read DCC (not remember exactly the message). then I change the cable that connect LCC with DCC & TCQA (small cable) then goes to A7 also but.

When I want to auto calibrate IGV the T core write after finish servo current null bias. and I find that actual position and servo current value and polarity is different from R&S. to solve the problem I change all cards have relation with servo and LVDT, but still the problem. and I download iocfg, const and seq to T core but nothing happen. also change servo valve with new one but still the problem.

Please any one can help.
[email protected]

 

Bayram_oglu,

I've read and re-read this post several times, trying to understand the problem(s) and the troubleshooting and the thought process you used in trying to resolve these problems. And, I have to admit, I'm pretty stumped.

About the only thing I can say with regards to the problem with the IGV LVDT feedback connected to <T> is that because of all the cleaning of the cable connectors you have mentioned that there is something related to this with the cables connecting the two IGV LVDTs which are connected to the TBQC card on <R>, and then "fanned out" to the three TCQA cards in <R>, <S>, and <T> via the three cables JFR, JFS & JFT between the TBQC on <R> and three TCQA cards in <R>, <S> and <T>. Or, there's something wrong with the TBQC card on <R>. Refer to the Signal Flow Diagrams in Appendix D of the Mark V Application Manual, GEH-5980, for details (<Q> Core - LVDT Excitation and Feedback Signal on QTBA/TBQC).

I do have one question: Why was it felt necessary to calibrate the IGV LVDT feedback? Did you check the calibration (the feedback versus actual, physical measured position) before deciding to "calibrate" the IGV LVDT feedback? When you did calibrate the IGV LVDT feedback, did you compare the as-found settings versus the new calibration settings for <R>, <S> and <T> to see how much, if any change, there had been?

At any rate, please write back to let us know how you fare in troubleshooting and resolving the problem. If you write back for more help, PLEASE provide more detail on the two IGV LVDT feedback signal readings for <R>, <S> and <T> from the AutoCalibrate screen. I'm referring to the position feedback values each processor thinks the IGVs are at.

 

Dear CSA..

i will say some details about what happened and what i did to solve the problem.

<T> was read default sys. and booting stop in A4. i checked and found that small cable that connect SLCC, SDCC&TCQA together was damaged and the SDCC, TCQA are struck. i changed them and <T> goes to A7.

after that i want to see servo's behavior and SRV, GCV both in normal condition but IGV servo have this issue:

in autocalibrate page when i did calibration this problem appear:

__<R,S> are normal but <T> appear (incorrect servo null bias current)

__ required position and actual position in <T> was different from R&S

__ polarity of current in R&S is different from T

__ LVDT for all <R,S&T> are same reading 0.7 in 32 degree,3.5 in 86 degree.

now here what i did to solve the problem:
i changed JFT cable in <R>, QTBA for <T>, TBQC in <R> also i changed TCQC in <T> ,but the problem still. again i changed the position between JFT & JFS in TBQC also the problem still.

i changed IGV servo with new one but also same problem.

to insure 86 degree open with out vibration in IGV ring i disconnect the servo coil two wire from QTBA in <T>..

i hope every thing is clear now pleased.
thanks again

 

Bayrum_oglu,

If the IGV position feedback in <T> is not approximately equal to the reference, then the servo current from <T> is going to be trying to make the feedback more equal to the reference. And if <R> and <S> are both okay, then the problem is the LVDT feedback that it "sees."

So, what you haven't been able to tell us is what were the two IGV LVDT position feedback signals that were being reported for <T> when you were looking at the AutoCalibrate display?

>__ LVDT for all <R,S&T> are same reading 0.7 in 32
>degree,3.5 in 86 degree.

It's <b><i>extremely rare</b></i> for the minimum stroke LVDT feedback voltage to be 0.7 VAC RMS <b>AND</b> the maximum stroke voltage to be 3.5 VAC RMS. <b>Extremely rare.</b> That's never happened to me. 0.7-3.5 VAC RMS is the possible linear range of travel; the actual range of travel usually results in less, sometimes a lot less, than 3.5 VAC RMS.

So what you've done by disconnecting the two IGV servo coil wires from <T>'s QTBA is remove the servo current of <T> from the IGV servo, so now only <R> and <S> are powering the IGV servo. The problem isn't solved, but the machine is running.

If you've changed all those cards and there's still a problem then it certainly sounds like there's a problem with the IOCFG parameters that are in <T>'s EEPROM. <b>AND</b>, there are probably some related Diagnostic Alarms.

Is there a file in F:\UNIT1 directory named IOCFG_T.DAT (for an <I>) or IOCFG_T.AP1 (for a GE Mark V HMI)? If either file exists, what is the file date/time and what is the file date/time for IOCFG_Q.DAT (or IOCFG_Q.AP1)?

Have you replaced the SDCC in <T>?

The problem isn't solved. And we don't know what the LVDT feedback for <T> is. You might try looking at the IGV LVDT feedback signals in the Pre-Vote Data Display, or DiagC (though I don't usually trust DiagC, it would be interesting to see what it's reporting in this case).

Even if the turbine is running you can still use AutoCalibrate to view values without affecting turbine operation or stability.

 

All readings for two LVDT's in <RST> during angle transfer between 32-86 are approximately same in auto calibration. The required position in <T> is different from <R&S> during angle transfer between 32-86 in auto calibration. therefore servo current is different from <R&S>. subsequently the actual position had been different, and the ring can't arrive 86, but stop on 82 degree. after I disconnect the <T> coil wire ,the ring arrive 86 degree.

You asked about IOCFG.DAT we have this file in IDOS. I replaced SDCC card.

Note:
I down (IOCFG, CONST&SEQ) to EEPROM on <T> core only then I found the constant value different in <T> from <R,S> in control constant page then I change the values that different and make all Same as in <R,S>

 

Bayram_Oglu,

I'm getting more and more confused all the time. And it's compounded by the fact you are not answering questions--for example, you were asked about IOCFG_T.DAT, not IOCFG.DAT. There should be no IOCFG.DAT. There SHOULD BE IOCFG_B.DAT (sometimes it's IOCFG_C.DAT and IOCFG_C.DAT), and IOCFG_Q.DAT. <b>If--and only if--</b>the site is knowingly using processor-specific I/O Configuration files should there be IOCFG_R.DAT, IOCFG_S.DAT and IOCFG_T.DAT.

And, you should be aware that when you edit parameters using the I/O Configurator that it <b>DOES NOT</b> edit any of the <Q> processor-specific files.

Now to the issue of how the IGV AutoCalibrate position reference for <T> could be different than for <R> and <S>, that's virtually impossible--presuming the <T> servo output driving is configured as a Type 43 regulator. Is that the difference you found in examining the I/O Configuration files? But that wouldn't appear on a Control Constant Display. I'm, really, REALLY confused.

You seem to be pretty satisfied the problem is resolved. I'm pretty concerned. I hope the fact that English is not your primary language is the cause of the miscommunication, and I suspect it's a part of the problem.

I wish that you could be more clear about what you did and what you found (identifying specific parameters changed), because a LOT of people read these threads trying to learn about Speedtronic turbine controls and GE-design heavy duty gas turbine operation and troubleshooting. It would be very helpful to many people to understand what was found and how the problem was resolved.

But, it's understandable that might not be easy or possible.

At any rate, we hope we were able to be of some help!

 

Dear CSA.

thank you and sorry about any confused happened. English is not my primary language.

i am trying to express about all what i saw and what happened during solving the problem. i am sure that the problem is still only what i did was making <T> gone to A7 and start the unit.

i will check about the files that u mention in your reply. the constants that i found were changed are in control constant page. i never entered I/O configuration page.

 

CSA..

We have these files in F\ unit1
IOCFG_C.BAK
IOCFG_C.DAT
IOCFG_D.DAT
IOCFG_Q.BAK
IOCFG_Q.DAT
IO_CFG.LST
IO_CFG.PRM

I want to open I/O configuration Editor page but I couldn't and this
message appear:
(Could not allocate 0x2d08 bytes of memory).

And in auto calibration page I checked that written in the top of page that servo no. Is 5 and type is 43.

Pls tell me what should I check?

Thanks....

 

Bayram_oglu,

I'm definitely confused.

I was working on a timeline of this thread and who said what and when. I'm either totally confused about what you've written and reported and responded to (and not responded to), or there's a huge disconnect.

Basically, I have a very difficult time understanding how the AutoCalibrate position reference for any of the three servo outputs could be any different than the other two--it just doesn't compute. One can't open and IOCFG_x.DAT file to see what's inside with any application other than the I/O Configurator. It's a binary file, with everything compressed and "coded" and it's not intelligible without a secret decoder ring (or the I/O Configurator).

The IO_CFG.LST file is an ASCII text file of each of the screens and the field values--BUT it's only as accurate as the last time someone clicked on 'LIST SCREENS' before exiting the I/O Configurator after making any changes.

It would be really helpful if you could tell us what Control Constant value you changed in <T>, and what you found it as, and what you changed it to. Because, again, I'm having extreme difficulty understanding how AutoCalibrate can be affected by any Control Constant value--because once AutoCalibrate is enabled for a servo output it bypasses the logic of the CSP (which is affected by Control Constant values), and just sends signals out to make the valve move to the ends of travel to calibrate the LVDT feedback. When one uses the Manual positioning feature of AutoCalibrate, one is still bypassing the CSP so Control Constant values would still not affect the reference--as far as I know. The IGV scale code (DGA) max scale has the same range (0-128) as other position regulators (which use PCT, which is also scaled from 0-128). So, I'm really, Really, REALLY struggling with how the position reference for one processor could be affected by any Control Constant, and how the position reference could be different for one processor out of three.

So, we're probably talking past each other here--meaning that we're not communicating properly.

If you could provide a list of Diagnostic Alarms, and their time/date stamps, we might be able to help but I doubt it. The processors have probably been re-booted several times and with the <T> servo coil disconnected there are other alarms which might be present which would be misleading.

I would really like to help with this problem--but the more I write the more I realize it's just not going to be possible to help unless I could be on site and could witness the issue for myself. I recommend you get someone knowledgeable to site to help with the problem, because the language issue and the delay in communication are just not going to help us help you resolve this in this forum. So, I'm even stopping work on the timeline; it's just too confusing.

I'd really, Really, REALLY like to know how this problem is resolved, so, if you could detail (heavy emphasis on the detail) what was found and how it was resolved that would be great!

Best of luck with this!