Mark5

R

Thread Starter

RAM

Hi,

If I want to measure the different voltages that are applied to SDCC card from the TCPS card with the help of a voltmeter, then where will I measure that and will it be advisable to do it while the unit is running?

Thanks & regards,

RAM
 
Most of the I/O printed circuit cards (the larger, 8-1/2-inch x 11-inch cards such as the SDCC) have small rings called test rings soldered on the card. They're not always located in the same place, and not every card has them--but most do.

Silk-screened on the card just "below" or next to each of the rings should be the indication of the voltage available on the ring.

The test rings are usually located very close to each other, and this author has seen them inadvertently shorted with a meter test lead (which resulted in a failed card or blown TCPS fuses)--so, no, it is not recommended to measure the voltages when the unit is running unless you have a very steady hand and a set of voltmeter test leads with insulated tips.

markvguy
 
Hi,

In DCC card I have seen the two poinst P5 and DCOM. These are the two points? What is this P5? That means if we kept one terminal of multimeter on P5 and other to DCOM, then we will get 5V, this P5 signifies that? Why only this 5V is so important to the DCC card?

One more thing, this IOMA card, it is actually not a card, it is only a PROM chip? Am I right? Actually I have never seen such a card on the DCC card. What are the functions that are performed by this IOMA chip? Is this chip important from communication point of view?

Thanks & Regards,
RAM
 
P5, positive 5 VDC supply. Required for proper operation of many chips and circuits. Yes, the red meter lead on the P5 ring and the black meter lead on DCOM will (should) yield approximately 5.00 VDC on the meter's display.

Yes, the IOMA is a chip(set) not a "card." If you want to know what functions are performed by the IOMA (which stands for I/O MAster), look at the "card" configuration fields of the IOMA in the I/O Configurator.

The IOMA is also involved in the automatic synchronization circuit/scheme (if used at your site).

markvguy
 
Another way to check the power supplies to the I/O cards would be to measure the voltages at the power cable connector. Use the Mk V Application Manual, GEH-6195, Appendix D, to determine what each wire should read with respect to ground (DCOM, CCOM, every xCOM in the Mk V is (should be) the same as earth ground).

markvguy
 
Hi, sorry for the late response. Can you please elaborately tell me what is this "DCOM" and "CCOM"? Power cable connector means it is the 2PL cable.

This CCOM and DCOM are both different?

Thanks,

RAM
 
DCOM = Digital Common
CCOM = Communication Common

One of the great things about SpeedTronic turbine control panels is that every xCOM is the same as earth ground. There are no separate ground buses as there are in many control systems. Even though they are labelled differently, they are all ultimately tied to station grid ground (in most power plants), which is the same as earth ground. (Some power plants have a separate control system ground, which while buried and earthed, is not connected to the same ground as the generator or the structural metal or transformer grounds.)

SpeedTronic turbine control panels--while some of them are more susceptible to electrical noise (induced voltages)--are not affected by grounding problems like some control systems.

markvguy
 
Hi,
Thanks for your reply.
This DCOM AND CCOM are at relatively zero potential.When i see the application manual- 6195G appendix D-55,there i saw there is a connector from <TCPS> card to <TCQC> CARD.It is a 16 pin ribbon cable(JC),where each pin represents some voltages(+1.225v,-1.225v,+2.63v,-2.63v etc.)

This is the power cable connector or any other is there as you say where we can measure the voltages supplied to the I/O cards?

One more thing while measuring voltage can we take either DCOM OR CCOM as reference,because both are at same potential.Is there any specific purpose to give two common points?

2.This is regarding "IOMA",CHIP yes i saw the I/O configurator,but there i found the "pulse rate definition" ,CPD definition and miscellaneous definition,which is the sync check screen.

but why it is called IO MASTER? and you also say it is a chip set,not a single chip?why i am asking is , in some document i have read that IOMA cards are actually referencesto the INTEL 80196 MICROPROCESSOR CHIP ON THE DCC CARD,and this the chip which actually checks the I/O CONFIGURATION,CURRENT REVISION ETC,AS MENTIONED IN THE I/O STATE A5 WHEN A PROCESSOR IS REBOOTED.

So that means as a set it comprises of i80196,32015 microprocessors and the PROM SETS(FIRMWARES).Is this firmwares are different from the firmwares located on the DCC card location U11 AND U12?

Please clarify me if i misses some thing.

Thanks & Regards
Ram
 
DCOM and CCOM had better be at zero potential...

This author is going to say that you remind him of himself when he was just learning Speedtronic Mk IV turbine controls and heavy-duty combustion turbine operation. He wanted to know everything about the Mk IV and how it was programmed and how it worked.

He quickly found out the most important thing to know was: How does the turbine operate? PL/M (Programming Language for Microcomputers) and Assembly Language never helped this author troubleshoot the inability to reliably start Steam Injection systems, or how to calculate Control Constants to control the Steam Injection flow-rate to control NOx without over-injecting and wasting feedwater and driving CO higher than permit conditions.

One of the really good--and really annoying--features of Speedtronic Mk IV, Mk v, and Mk VI turbine control systems is the Diagnostic Alarm feature. Really good because it reduces the need to understand so much about the internals and "behind-the-scene" operation of the turbine control system because those functions are monitored and Diagnostic Alarms are generated when a problem is detected. Really bad because many of the Disgnostic Alarm messages are cryptic to the point of being impossible to understand and because there is no real trouble-shooting guide for them and because it's not possible to see the code/sequencing which generates the alarms.

In the Mk V, there can be more than 3,000 Diagnostic Alarms! If any power supply voltage is out of tolerance, a Diagnostic Alarm will be generated. If there's a problem with communications between I/O cards, a Diagnostic Alarm will be generated. (It might not be apparent which Diagnostic Alarm is applicable, but one will be generated.) This author has learned to immediately respond to and resolve Diagnostic Alarms--they are there for a purpose (though sometimes it seems to just be to annoy operators and technicians) and will alert one to impending problems or even help pinpoint the cause(s) of Process Alarms

Try as he might (and he has tried mightily!) this author cannot convince people of the importance of Diagnostic Alarms. Why? Because, for the most part units run and continue to run with a number of Diagnostic Alarms. Most people, unable to decrypt and understand the Diagnostic Alarm messages and in the absence of a proper troubleshooting guide (which doesn't exist for the Mk IV or Mk V), don't even bother to try to troubleshoot them. As long as the unit is running, they just ignore them.

As has been said before on this forum, many Diagnostic Alarms are simply the result of improper I/O Configuration--leaving T/C inputs enabled with nothing connected to them; leaving servo-valve outputs enabled with nothing connected to them; etc. This author has visited a number of sites which had SO many Diagnostic Alarms they could not all be displayed on the <I>--there were more than 64 Diagnostic Alarms, which is the maximum alarm queue number which can be displayed. And, those units were all "commissioned", in service, and generating power! Simply disabling unused T/C inputs and unused servo-valve outputs resolved many of those Diagnostic Alarms, so many that once the more recent Diagnostic Alarms could be displayed the erratic and intermittent operation of the units were solved by resolving the Diagnostic Alarm messages which couldn't be displayed because of those that were simply the result of improper I/O Configuration!

Another thing which contributes to the inattention paid by operators and technicians to Diagnostic Alarms was the inattention paid to them by commissioning personnel--who suffer from the same cryptic messages and lack of a troubleshooting guide. If the commissioning/start-up engineer isn't bothered by them and doesn't "feel the need" to troubleshoot them, then they must not be important and operators and technicians can ignore them. Most operators and technicians ignore any alarm that doesn't result in a turbine trip or shutdown. And many operators and technicians initiate a MASTER RESET action any time an alarm is annunciated to see if that will "clear" the alarm and allow it to be reset--without ever bothering to understand why the alarm was generated. If it goes away after a MASTER RESET it wasn't important; if it doesn't go away after a MASTER RESET and the unit didn't trip or isn't in an autmoatic shutdown, it can wait until somebody has time to troubleshoot it.

Don't misinterpret these next questions; this author believes that questions are good things and has learned a great deal from researching the answers to questions he couldn't answer immediately. Understanding why a chip/chipset is called one thing or another is much less important than understanding why a solenoid isn't energized when it should be--and even less important than understanding when a solenoid should be energized and when it should not. Granted, sometimes understanding why something is called what it is (like "droop" speed control!) can be helpful in understanding why something was done the way it was done, but in the grander scheme of things does understanding how many chips make up the I/O Master and what exactly it does make more sense than being able to troubleshoot an Exhaust Overtemperature Alarm or being able to determine if the exhaust temperature is correct for the given conditions?

Can you "read" the CSP? In other words, can you determine from a rung or group of rungs how a particular auxiliary is supposed to operate? For example, can you say when the Turbine Compartment Vent Fan starts and when it will stop? Can you say when a high Turbine Compartment temperature will be annunciated and what other action(s) might occur when one is detected and annunciated?

Can you derive the formula for the CPD-biased (or CPR-biased) exhaust temperature reference from looking at the BBL? Can you determine when a high exhaust temperature spread will be annunciated by looking at the BBL and associated sequencing?

Do you understand what an inverted contact input is and why it's inverted? Can you read the input point voltage with a voltmeter and determine if the contact is open or closed? Can you tell from the CDB (Control Signal Database) pointname when the logic should be a "1" or when it should be a "0"?

Do you know where to find the setpoint for the High (Alarm) L.O. Header Temperature switch (26QA-1)? Do you know where the Normal L.O. Tank Temperature switch (26QN-1) is located?

Do you know what hardware ("Berg") jumpers should be in what positions to enable/disable a solenoid output?

Again, this is not meant to discourage you from asking the questions you are asking--but the answers to many of them will not help you troubleshoot your turbine compartment vent fan when it doesn't shut down or doesn't start when it should. Understanding why the IOMA is called the I/O Master isn't going to help you understand if the automatic synchronizing logic isn't working right and you can't synchronize the unit to the grid. Understanding which chip/chipset comprises the IOMA isn't going to help you understand why you aren't making rated power output and what the exhaust temperature should be for a given CPD (Compressor - Pressure, Discharge).

Diagnostic Alarms will tell you if the I/O Master is working properly (regardless of the number of chips which make up the I/O Master or exactly what it does). Again, decrypting the Diagnostic Alarm messages can be a daunting task, but you should rest easy knowing that the "background stuff" if being taken care of.

Now, if you were designing a turbine control system or trying to reverse engineer a turbine control system these questions might be applicable and important. Hmmm, is that what you're trying to do?

But if you're just trying to understand how to troubleshoot turbine-generator operation and keep a unit running at top power output, the answers to these questions aren't going to help you do that.

Now, to answer your questions: The power supply cable that was referenced has four or five individual conductors; it is believed one of them is black and the others are red. The conductors are approximately size 14AWG (American Wire Gauge). The cable runs from from the TCPS to the various I/O Cards in the processors (<C>, <R>, <S>, and <T>) as well as to the appropriate TCDA cards in the digital I/O cores (<CD>, <QDn>). Usually one can measure the voltages by slightly lifting the connector and exposing the pins on the card--but be careful--don't short the pins together! Or, you're going to be asking which fuses on the TCPS card are for which power supply (there's no answer to this question--if any fuse is blown it should be replaced, and if it continues to blow, then the cause should be troubleshot and resolved).

The ribbon cable you are referring to is most likely for power supply monitoring, as the Signal Flow Diagrams in Appendix D indicate.

Printed circuit card designers seem to want to have "isolated" commons (grounds) for some circuits, and then tie them all together at some point--either on the card or at the ground bus bar in the Mk V. (The ground bus bar is usually in the upper left corner of the panel.) But, the philosophy with Speedtronic turbine control panels is that any common is the same as ground--which makes troubleshooting much easier!

Regarding the IOMA "card", who knows why it was called the I/O Master? Remember--the DCC in 'DCC card' stands for Drive Control Card. It was one of those printed circuit cards which the Turbine Products division was forced to use when designing the Mk V because the Drives Division at GE Drive Systems (which is where the Mk V was designed and manufactured) used them--and the then-Plant Manager decreed, "To the extent possible, thou shalt use existing hardware to build the Mk V--thereby reducing the number of components built in this factory!" The IOMA designation came from the Drives Division printed circuit card designers, it is believed, and was adapted for use in the Turbine Division's turbine control panel application.

This author is going to be away on vacation for the next three weeks and will have limited Internet access, and an even more limited desire to log on and answer turbine control panel-related questions when he does log on! Since he has no immediate acces to a Mk V turbine control panel as of this writing, it's not possible to say which chips are related to what microprocessor on the Drive Control Card, er, uh, the DCC card.

In the meantime, it is suggested that you review the above questions and give some serious consideration to whether or not understanding which chips have what power from which cable will help you be a better technician--or, if you're trying to reverse engineer the Mk V, it is recommended you reconsider your mission in the interest of trying to save your sanity. Some things have no rhyme or reason, and many things associated with the Mk V are downright maddening.

markvguy
 
Yes you are correct we should be more concern for those above mentioned questions, i never misinterpret your questions or comments. That is why when you say refer that thing in manual i immediately refering the manuals, search the document and immediately comes back to you whatever i get and your comments is always fruitful and great learning for me.

I have got a lot of very very useful information from you which really helps me to understand the system so i will not rather i should not taken your word in a wrong manner. It is also a way of learning for me and do the things correctly.

When i ask any questions, it is not that simply i put a question, but as you can see in my questions, i always give enough descriptions and reasons for asking those questions. Asking someone questions is very easy which is not important, but before asking that how much we drilled down ourselves to find an answer for that is really important. This is what personally i feel.

Ok no problem we should always take care about what we should ask and why, and next time onwards i will take care of that.

Thanks & Regards
RAM
 
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