PLC Module

Discussion in 'General Electronics Chat' started by R!f@@, Jan 24, 2014.

  1. R!f@@

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    Check PDF for detail..Model is K7M-DR20UE
    OK .So I serviced one, couple of years ago. I'd say 3 to 4 years
    The PSU cap blow so it was not a big deal even though I assume it was an input voltage overload as the varistor was in pieces too

    I did not think of the input much then.

    This was used in an ICE PLANT on a fishing dhoni.
    The Panel has 4 wire 3 phase. Did not make any measurements before but instead I checked for power at workshop and just connected it to the plant and worked till yesterday.

    Captain called and I went, checked no power. They said they put in the second PLC that was serviced by another party and it too was dead.
    Checked and found the fuses fried in both. so this time I checked the mains. It was at 238VAC. Unit can take 240VAC.

    The one I did not service had the cap dried. Funny thing is the Cap was open upto some extent but the fuse was melted. I wondered why the fuse blew. Cause in most cases the a dry cap will result in shut down PSU. Not blow to smithereens...:confused: Right?

    The One I fixed before, I cannot get the varistor so I left it out. The cap was blown then, even today tht cap is fine cause I checked this time. But I did replace tht varistor cause now I got plenty.
    This ones fuse was blown too with the main tracks and also line filter inductor was fried. I replaced the STR just in case, and I did check the old one for shorts, but did not find any.

    Now both works fine, the power tht is.

    Q1.) Could the 238VAC was a problem. I am thinking of reducing the voltage to 230VAC from genset. So at full load it would be around 220VAC give or take a few.

    Q2) They bought a new PLC then cause the old one failed. I do not think they were able to use the new one. I asked a lotta question trying to find if they used the new PLC in the machine. What I figured so far was tht it did not.

    Here is where I get stuck.

    The PLC has to be programed right?
    Cause a new one would just not work in the machine if it is brand new without a program...?? or do they come out preprogramed ? If so what is the use of "P" in PLC.

    I do not think the guys who made the machine gave them a new one...:confused:
    I think captain bought it or something..!

    Another question is can I get the file out from the PLC to copy it to a new one like in IC chips we use and get the HEX file out ...u know what I mean :D

    What tool do I need ?
     
    Last edited: Jan 24, 2014
  2. MaxHeadRoom

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    Sounds like the AC may be fluctuating at some point, but OK when you measure it!
    A PLC will come blank, unless this was a unique application and you got a replacement from the OEM.
    I have never heard or seen that particular PLC, but generally you need software which is often proprietary, from the manuf. of the PLC.
    If they are getting failures and the PLC comes blank, it defiantly would pay for them to have a back up of the program.
    With the software you can usually upload/download to a lap-top or P.C.
    Some kind of power regulator may be in order, the Sola regulators just for the PLC should not be very large or expensive.
    Max.
     
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  3. MaxHeadRoom

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    I see on one site it states:

    KGL-WIN application is free of charge programming tool for Master-K series.

    This application allows programming, debugging, project down- and up-loading and on-line program edition. Programming language is very simple and easy to learn. It supports IL, LD programming methods.
    Max.
     
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  4. R!f@@

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    I doubt they would use a solar... ! U dunno these fisherman's.

    Tomorrow I am going to reset the genset to 225VAC at no load first. Check the new one first for the software and then the second one.

    Thanks max for the heads up om the programing tool. Will check it after work.
     
  5. MaxHeadRoom

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    I see the PLC is rated 85vac to 264vac supply.
    Using a small 240v/120v control transformer running to at a lower voltage should also give some leeway if spikes are happening.
    Max.
     
  6. R!f@@

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    OK. So I manage to reset the genset to 225VAC. First it was at 240VAC.

    The Manual of the plant says 380VAC is needed at 3 phase to operate properly.
    Checked after adjustment and found 385VAC between faces.

    So I guess it's all good. The New PLC was running when I left. So far no house call so I guess it's all good. I'll know tomorrow for sure.

    The Old PLC is switching off after few minutes, it seems the supply is shutting down. Need to check for more caps but I think I will get new parts. The cap I bought from here was lower than rated value so it could be an issue.

    I have a question.

    The voltmeter on the front panel of the plant jumped up to 500V when the compressor switched on. So it was like +112VAC variation. From 380VAC to 500V. It was a spike from compressor start up surge

    Any idea what the 220V variation would be when it's phase to phase varies from 380VAC to 500VAC. Need to make sure how high can the 220VAC line would jump.
    The varistor I replaced was rated for 300VAC. The original one was rated fro 350VAC.

    PS..the PLC label says max is 240VAC not 265VAC

    At first no PLC ran the program. Head to bust my head a lot to figure out why the two behave the same. some bozo had switched on the Cnet ROM switch in each PLC. Fisherman fixing a PLC. Go figure.
     
    Last edited: Jan 25, 2014
  7. MaxHeadRoom

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    Sounds like it needs some kind of delay to power the PLC after the generator has been fired up and settled?

    265v was what the on-line User manual stated.
    Max.
     
  8. strantor

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    If the software is free, download and install it, and go immediately to the machine and transfer the program out of it to your computer for safekeeping. Sounds like this thing is on its last leg and if it goes, and you can't fix it, you'll have to replace the PLC. If you replace the PLC and don't have a program to transfer to it, you're screwed. You'll have to get it from the OEM, which may or may not be possible (are they in business still? do they speak your language? is anbody there willing to help you without thousands of dollars? Do they consider their programming intellectual property?). You'll be screwed if you don't. Trust me, been there, done that. Any time I work on a machine PLC, I save the program and back it up. If I make a change, I save the modified program and original. Next time I go out, I compare programs and see if anybody else has been tampering with it. This has saved my ass so many times. Customer calls "PLC is dead, OMG, we don't have the program! What will we dooooo...?????" "Now worries, I have everything backed up."
     
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  9. R!f@@

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    Could not find the KGL software for download u know ?
     
  10. R!f@@

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  11. strantor

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  12. R!f@@

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    I was asking about the decrypting thingy.

    I got the KGL.

    Hey strantor...Have u used these Master K PLC's? Any pointers ?
     
  13. strantor

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    Nope. Never heard of em. Must be an obscure Chinese thing.

    Pointers: In some (most) PLC software they use the terms "upload" and "download" which are probably backwards from what you are used to (as in downloading means to your computer).

    Transferring from the PLC to your laptop is uploading
    Transferring from your laptop to the PLC is downloading

    DO NOT BE A DUMBASS AND DOWNLOAD A BLANK PROGRAM TO THE PLC.
     
  14. MaxHeadRoom

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    [​IMG]If they have a failed PLC and you can repair the P.S. you could download the S/W and play with it, if it has a Memory chip, blank or not.
    Max.
     
  15. R!f@@

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    They are LG Master K series ...dumb ass ? :D

    Me think same :D

    That's what I wanna make sure.

    This part scares me :eek:
     
  16. R!f@@

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    One is already running. New one.
    Old one, I have it but PSU is shutting down after a few minutes.. Problem to be solved but the program is there. It runs. I checked.
     
  17. strantor

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    Good, it should. Be careful. There's no undo button for that.
     
  18. MaxHeadRoom

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    Apparently they are made by LG, these started out as a large Taiwanese semiconductor manuf, now of course they are into domestic electronics, the TV's are everywhere!.
    I had a look at the PLC features and options, they look very impressive.
    They appear to have 3 wire RS232 communication only, so you would need a PC with a 9pin RS232 socket, unless you can manage to get one of the USB to RS232 convertors to work.
    I like the wording on the Mitsubishi PLC's as it gives the option of receive file from PLC or Transmit to PLC, so there is not much confusion.
    Max.
     
  19. strantor

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    I didn't realize it's LG. Still not interested, practically. If I ever encounter one in the field, I'll become interested real fast.

    I have a hardware serial port on a brand new laptop! Crazy, huh? I told my IT guy I needed one, fully expecting not to get it, and he came through! amazing.

    I also Like Omron's CX-Programmer. It has the same upload/download nomenclature as GX Developer. Actually I prefer Omron PLCs & software over AB, Siemens, mitsu, IDEC, Koyo/AD, et. al. I May be somewhat biased because, as someone who works for an Omron distributor, I encounter a lot more Ormon PLCs than most Field Service guy probably do, and I have gotten used to them.
     
  20. MaxHeadRoom

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    For field use, I picked up a couple of IBM ThinkPads, they are very cheap on ebay, being rugged and having all the I/O features you might come across in the field.
    PCMCIA, floppy, CD, Ethernet, USB, RS232, Parallel port, line in.
    Max.
     
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