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Thread: Unrecognised DMM

  1. #1
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    Unrecognised DMM

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    Hi guys,

    I've been running Roast Monitor (v2.33) and a victor DMM for nearly 500 roast without an issue; however, on the weekend the computer won't recognise the DMM. It comes up with "USB Device Not Recognised".
    I was wondering if I could pick some brains for what might be going on.

    - have been using dedicated computer from day 1. it's not connected to net nor been updated.
    - I plugged the DMM into another computer and it also says that it's unrecognised as well.
    - the USB port that I use works for other USB devices.
    - I'm not aware of doing anything different from last successful roast to this weekend.

    This leads me to think that it's the DMM cable (optical RS232 to USB) which is faulty.

    When I open Roast Monitor, I'm sure it comes up with an error that I don't normally see when I start RM but haven't connected the DMM.....but I think this is just because it rarely happens and don't pay full attention to the error wording.
    I thought it use to say 'meter is not switched on' (or something like that) but now it comes up with a consoleapplication error and says ERROR: No HIDs found.

    So, if its the cable......my understanding is I probably won't be able to get a replacement? and best bet is to get a heatsnob?

    Any thoughts would be appreciated.

    Thanks
    Peter

  2. #2
    Life-long Learner DesigningByCoffee's Avatar
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    Hi Peter
    A few times I have bumped the RS232 button while moving stuff around - then get that message next time I load it up … might be the first place to check?
    Cheers Matt

  3. #3
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    Is an optical RS232 to USB the same as a RS232 to USB? If so you can get them from Jaycar. http://www.jaycar.com.au/usb-to-db9m-rs-232-converter-1-5m/p/XC4834

    Just go buy it. I think you have a couple of days to return it if it doesn't work.

  4. #4
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    Seem to recall this happening - I found it was the optical plug being plugged in upside down from memory. Haven't got it anymore, otherwise I'd check.

  5. #5
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    Thanks for the ideas.

    Matt - It's definitely not the RS232 button. Bumped it many a time.

    MrFreddofrog - the Victor DMM uses a optical isolator, mounted in a proprietary plug that fits their DMM. Not the serial style plug in the jayccar link provided.

    Simonko - Unfortunately it's not upside down either (just tried it). I've never experienced that problem having removed the plug on multiple occasions.

  6. #6
    Mal Dimal's Avatar
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    Quote Originally Posted by simonko View Post
    Seem to recall this happening - I found it was the optical plug being plugged in upside down from memory. Haven't got it anymore, otherwise I'd check.
    Shouldn't make any difference really.
    Of course, there may be some chaff or other detritus blocking the optical path in the meter's optical socket but I'd go with Matt's suggestion first plus blowing out the optical socket in the meter. See how you go after that...

    Mal.

  7. #7
    Mal Dimal's Avatar
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    Quote Originally Posted by Roubaix View Post
    Thanks for the ideas.

    Matt - It's definitely not the RS232 button. Bumped it many a time.

    MrFreddofrog - the Victor DMM uses a optical isolator, mounted in a proprietary plug that fits their DMM. Not the serial style plug in the jayccar link provided.

    Simonko - Unfortunately it's not upside down either (just tried it). I've never experienced that problem having removed the plug on multiple occasions.
    Ah, Ok then...

    You may have to verify that the LED in the meter is working. If it is, then you will have to check the optical end of the cable. There may be something coming adrift on the tiny PCB inside...

    Mal.
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  8. #8
    Super Moderator Javaphile's Avatar
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    A couple easy things to check. Has the environment changed? Specifically is there now more light on the DMM than previously? Have you tried new batteries in the DMM?

    Swap out the batteries for new ones and after making sure the cable is fully plugged into the DMM wrap a heavy dark towel or similar around the end of the DMM with the cable to make sure no light is getting to the plug/jack and see if it now works.


    Java "Oh the light, the light!" phile
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    Toys! I must have new toys!!!

  9. #9
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    Just popped open the plug - and low and behold a wire appears to have come loose.
    Thanks Mal.

    just to clarify - I hate computers and electronic things, more a mechanical type person.
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  10. #10
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    Behmor Coffee Roaster
    Quote Originally Posted by Dimal View Post
    Shouldn't make any difference really.
    Of course, there may be some chaff or other detritus blocking the optical path in the meter's optical socket but I'd go with Matt's suggestion first plus blowing out the optical socket in the meter. See how you go after that...

    Mal.
    Agree it shouldn't make any difference, especially as the plug wasn't keyed. Chaff wasn't the issue in this instance (although chaff did block once). Every time it happened I just turned the plug over and it was fine. Probably just a slight misalignment.



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