We have MARK V system controlling GT-3 at our site... The AIFH (Air Inlet Filter House) has DP Gauges to monitor the "Delta P" across the AIFH.... We have a DP Transmitter of the correct range in hand and so we are tempted to add it to the system so that the DP values are available in the remote control room in <I> station... We have identified spare cables (the commissioning time leftovers for pressure switches 63TF-1, 63TF-2 and 63CA-1) that run from MARK V panel to the field where AIFH set up is...

1) How can it be done?

2) Where in MARK V can I find the 4 - 20mA signals of PCD and P2 Pressure scaled to engineering units?

au revoir
Rahul

 

There is a section in the Mk V Application Manual, GEH-6195, on adding inputs and outputs to the Mk V. Look that over and if you have any questions, feel free to ask. The step-by-step procedure would require more space than Droop speed control descriptions.... It's not difficult, there are just a LOT of steps, which all must be performed in the correct order, including downloading to Mk V and re-booting the processor(s) downloaded to, and re-booting the <I>.

The biggest help you give yourself is to make sure you have a back-up of EVERY FILE on the F: drive before you begin, and know how to recover from those back-ups if you need to. Also, make yourself a check-list of every step you, and check each one off and leave room for places to make notes about anything which you feel uncomfortable about (error messages, warning messages, etc.).

When connecting a 4-20 mA signal to the Mk V turbine control panel, you want to use twisted, shielded pair wiring. If you are contemplating using non-twisted, non-shielded, single conductors in a multi-conductor cable, you will most likely have electrical noise problems with the 4-20 mA input, which will basically render it useless.

Just as important as using the correct wire/cable, is the termination of the shield drain wire of a twisted-shielded pair. The drain wire should only be terminated at one end of the cable, and the general consensus for terminating shield drain wires is to terminate them at the source of the voltage for the signal--in this case, it would be the Mk V. You would want to terminate the shield at the shield ground terminal points at either end of the TBQC or CTBA (depending on where you decide to terminate the signal).

You also need to make sure you set the hardware ("Berg") jumpers for the input correctly; again, see the App. Manual for details.

You should have an I/O Report that was provided with your Mk V. It's essentially the print-out of the file F:\UNIT1\TC2KREPT.TXT. You should be able to look through that document (there is a little bit of a "document reading aid" in the first couple of pages) and find most signals related to hardware.

Another good place to look (electronically) for signal names is F:\UNIT1\LONGNAME.DAT. This file is a list of signal names and their descriptions (this is where the CSP and the CSP Cross-reference gets the signal name descriptions from). You can open the file with an ASCII text editor or -file viewer and search for "P2 pressure" and "CPD" (the latter IS the CDB (Control Signal Database) name for the compressor discharge pressure in the Mk V).

You can take your back-up floppies and install them on another PC in a separate directory and use any ASCII text editor you wish to look at the files. That way you won't be nervous about accidentally "harming" any of the files (which is what most people worry about when even opening a file to view it). Just remember, if you open a file with an editor intending only to look at the file (view it) and when you close the file if it asks you if you wish to save any changes--just answer No. That way, any unintentional changes which might have been made WON'T be saved.

How's the Water Injection situation?

markvguy

 

Thanks... Will try that out if I feel confident after reading the manual... As such it isn't urgent... Will go thru the manual as you suggested...

Water injection problem has been solved... This weekend only.... A GE representative was called. I'll have to find out today what was the problem cos I was busy with a DCS problem in the plant.... I had requested the GE rep to stop the <I> station and fix up a new Floppy drive I had procured just for the purpose... Wish he's done that.... Didn't check it out when I left the plant... Hopefully, will see it today....

Thanks again,

au revoir
Rahul