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  1. #1

    Meldas M0 - No work offsets? Tool change error?

    Crossposted to the other Mitsubishi control spot.

    I have a Long Chang LC-16CV knee mill with a Meldas M0 control on it. It appears that it didn't come with the (factory optional) ability to set work offsets (G54, etc). The control itself is capable of it according to the manual, but the screen where that info would be entered is not available on this machine.

    How would one go about getting those to work? Is it a combo of dip switches or something in the control cabinet? An add-in card? Something that gets typed into the control?
    Please help, I'm currently stuck using the machine origin coordinates which makes programming the thing nightmarish.

    Second problem: If I call a tool change (for example T1 M6), the machine throws a "sequence alarm". Haven't found any good solid info about what that means or how to get around it. Sharp doesn't want to help because it's too old, Mitsu are nice but they only have limited info also due to age, and I don't speak Mandarin so I can't get anything out of Long Chang in Taiwan.

    I should mention that this machine doesn't have an automatic tool changer, only a power drawbar system controlled with some buttons on the head. I suppose I'd expect an M6 command to pause, home the Z axis and await manual tool change, but it doesn't even do that.

    Possibly related to the tool change issue - when I got the machine it had a dead memory battery, since replaced. I reloaded all machine parameters and canned cycles by hand from the machine manual, but in the back of the manual there's a picture of some 1's and 0's in the "sequence" screen that I think need to be reloaded just like the other parameters, but nothing I do will make them stick. I can enter them, but they disappear as soon as I power off the control.

    Both these issues mean that I'm currently limited to very rudimentary programs, mostly handwritten and single-tool. Any help with them would be most appreciated.

  2. #2
    Join Date
    Jul 2009

    Re: Meldas M0 - No work offsets? Tool change error?

    On the no work coordinate offset, Do you have a memory protect switch? If so, try turning it to the other position. That might fiix that problem,

    Did you format the memory? Did you try

    As for the tool change,If you don't have a tool changer then the M6 code is useless to you. The best way to handle that case would be to touch off all your tools and put the values in the tool offset register. Then in your program do something like this where you want to change tools, I don't know how familiar you are with G-codes.


    When the machine stops, You would then go to manual and manually change tools. Then back to MEM and cycle start. Don't forget to call your tool length offset and turn the spindle on,


    G90 G43H1 G0Z3.

  3. #3

    Re: Meldas M0 - No work offsets? Tool change error?

    Thanks for the suggestions, I tried enabling/disabling the memory protect settings, and unfortunately it didn't help.

    I did format the memory, that was its own hassle to figure out but I got it.

    I am somewhat familiar with Gcode, I spent a couple years in a shop operating a Haas VMC, and I have been playing with 3d printers as well. It's just a matter of learning the flavor of Gcode this thing likes, because it's definitely different than my previous experiences so far.

  4. #4
    Join Date
    Jul 2009

    Re: Meldas M0 - No work offsets? Tool change error?

    What manuals do you have?

    Can you send files to/from the control?

    I could give you a sample program to look at if that would help but my Meldas MO machines had tool changers so, you would have to bear that in mind.

    You could try the G92 to set your work offset if you can't set the G54 position.

  5. #5

    Re: Meldas M0 - No work offsets? Tool change error?

    I have volume 1 and 2 of the Meldas M0 instruction manual (700+ pages overall), and the machine manual, which is maybe 25 pages at best, and has the basic machine specs, a couple general wiring diagrams, and the machine parameters, and that's it.

    I can read and write to the machine over RS-232.

    Thanks, I'd appreciate having a sample program just to compare, even if it's not exactly right in all the details.

    I called Mitsu today and they said if I want features unlocked, I need to call the machine manufacturer, and then THEY need to call Mitsu so that they can write the program to unlock, then have a tech come out and punch it into the machine.

    Converting this beast to LinuxCNC is seeming like a better and better deal

  6. #6

    Re: Meldas M0 - No work offsets? Tool change error?

    Not sure if you are still working on this but I might be able to help on the work offsets. I just solved this problem for my Leadwell mcv-0 today. I have most of the meldas m0 manuals including maintenance and specifications. I'm going to break them apart, scan to pdf and upload them for anyone that needs them. It really seems like a good controller.

    Work offsets may not be set from factory. On diagnostics page 7 you are looking for a "1" in line 5 bit 4. On my machine the work offsets showed up by pushing page down in offsets but showed "error keyin format".

    You can try the hand written parameters on the attachment below. They are inputed by enabling the parameter screen from Diagnostics page 6 i believe. Type H1000 then change bit 2 to a 1 and push input twice. You can then see the hidden parameters on the second parameter page. These worked for me but make sure you record what you got first.

  7. #7

    Re: Meldas M0 - No work offsets? Tool change error?

    This is exactly what I needed, thanks!
    I'm still trying to figure out their encoding scheme, it seems like the machine parameters are in hexadecimal but these bits are binary?
    Here's a shot of my current parameters:
    What would I change if I just wanted work offsets?

    Luckily I have all the machine parameters hardcopied in the machine manual, so I can afford to mess with them without fear of permanently screwing them up.

  8. #8

    Re: Meldas M0 - No work offsets? Tool change error?

    I haven't figured it out yet, but I changed mine from the picture below to the first s0-s4 hand written on that page I sent and it fixed the problem. I was on my way out the door and they are from the previous owner, so I just did all of them at once. If you change them one at a time let me know what you find.

  9. #9

    Re: Meldas M0 - No work offsets? Tool change error?

    So I think it's hex to binary with a pattern going from p1 7654 and then p1 3210 then p0 7654 and p0 3210. The next would be p3 7654 then p3 3210 then p2 7654 then p2 3210. So lets say that you want work offsets. That's going to be s3 on the parameters and it's going to be the first letter. Your's is currently an E or binary 1110. That enables just the first 3 in that row. You want all 4 so change it to an F, or in binary 1111. That should enable work offsets.

  10. #10

    Re: Meldas M0 - No work offsets? Tool change error?

    It worked! I now have work offsets.
    I'm currently trying to make up an excel sheet that will let you check all the boxes for features you want, and it'll spit out the corresponding hex values for you to type into the control.

  11. #11

    Re: Meldas M0 - No work offsets? Tool change error?

    Good to hear. This is a better scan of the first page and a second.

  12. #12

    Re: Meldas M0 - No work offsets? Tool change error?

    Nice, I added those to the sheet. I'm not 100% sure about S5 since there's only one line of bits, but all the others work and correlate with my machine's existing featureset.

    Here's the sheet so far. It only 100% works in Microsoft Excel, not Google Sheets because the checkboxes don't translate properly. I haven't tested it in LibreOffice or OpenOffice.

  13. #13

    Re: Meldas M0 - No work offsets? Tool change error?

    I tried it out in Excel and it works great. Thanks for putting that together.

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