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Thread: Help: RMI Galvo Laser Engraver

  1. #1
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    Default Help: RMI Galvo Laser Engraver

    I recently purchased a laser engraver off ebay. I am new to galvo lasers and need help with driving it. Originally the system came with a DAQ card but that's long gone. The marking head has a 37 pin connector for the computer interface. I am curious if there is another was to communicate with they head other than the PCMCIA DAQ card. Any help getting it connected and talking to the software would be appreciated.
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  2. #2
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    Default RMI Manual

    Here is the manual...
    Attached Files Attached Files

  3. #3
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    Please see image annotated.

    At 8 watts you need Optical Density Six, ( OD6 ) safety glasses to work on this if you have to adjust the hardware. Its Q-switched, so the pulses are insidiously dangerous if viewed by the naked eye. Reflections are an issue with that short pulse length. Even diffuse reflections are quite a hazard.
    The only way you cna view 1064 is with a CCD camera or IR image converter tube (Find-R-Scope) and even then a silicon CCD or CMOS imager is barely sensitive to 1064.
    To get 8 Watts of Q-Switched IR from Vanadate, you would have between 16 watts to 30 watts of pump diode at 808 nanometers as well. SO if you open up the laser head, you need glasses for both 808 (OD 6 Minimum) and 1064 nm.

    1064 burns the surface of the skin, 808 dives down into tissue and hits nerves/veins/arteries as well as burning the surface of the skin.

    BE careful.

    Steve
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  4. #4
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    Default

    Can you show what's on the other side of that 37 way connector? If it's one of the common marking interface cards, you may be able to drive it with free software without too much additional hardware.

  5. #5
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    I have the manuals and the software from RMI. It's the connection from marking head to PC that I need. Like I said, i dont have the DAQ card and cables that RMI originally provided with the system for the control interface.
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  6. #6
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    The AD660's on the control board are DAC's...
    "There are painters who transform the sun into a yellow spot, but there are others who, with the help of their art and their intelligence, transform a yellow spot into the sun." Pablo Picasso

  7. #7
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    Default Revisit

    So i finally had some time to take another look at this engraver. I have been poking around and found that pins 2-9 on the 37 d-sub go to the data pins on the AD660s (pins 5-12). I connected a 9v and pot to the Vout of the dac's and confimed that moves the galvos. My question now is how do i connect and use this laser without the daq card?

  8. #8
    mixedgas's Avatar
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    Buy a controller
    Make a controller

    However, you need a great deal of laser safety and cooling and power interlocks for your own safety.

    For a quick trial you can use something like this: With say GRBL or some of the other image engraving software that supports G-code

    DIY STEP/DIR LASER GALVO CONTROLLER : 5 Steps (with Pictures) - Instructables (Yes I've tried it, it works "OK", not great, but OK)

    Otherwise you have to decode the logic on the board. There is a one-shot chip on the board which suggests the system derives its pulse command and pulse length from that board.

    Attached is a start., a finite, minute start on decoding the logic..

    Steve
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  9. #9
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    Post

    Thanks Steve. Believe me, I understand the safety concerns. I have worked around large CO2/fiber cutting machines (60x120) for many years, and yes i know these are different from this engraver. If i stick my hand into our CO2 machine (4000W) it gets cut off..... it will be cauterized so no big deal. We will not start the diode without using the enclosure and interlocks. The board in question is from the scanning head and is completely separate from the laser diode controller.

    Yes, we could buy or make a controller for steering the galvos but what i really want to do is keep this control board in place and figure out how to communicate with it using the original software running on xp. Don't know if this is possible without finding the obscure and discontinued pcmcia daq card. Thanks for the decoding start. I forgot the attached image on my last post. As you can see i have been slowly tracing connections.

    Here is a link to the daq card https://accesio.com/MANUALS/PIOD24.pdf

    RMI has told us its not possible to connect without the card. Thanks for the help!
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