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Re: [mill_drill] new article:A Possible ShumaTechR 350 with 550 Daughterboard Power Up Fix

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  • Jerry Durand
    I wish people would put better power on resets into boards and chips. I ran into a problem with a TI processor I used in an industrial application, on power
    Message 1 of 5 , Jan 26, 2013
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      I wish people would put better power on resets into boards and chips.  I ran into a problem with a TI processor I used in an industrial application, on power up no matter how slow the rise time it held itself in reset until an appropriate level was reached.  However... once the power up reset was happy with the power, it wouldn't generate a reset signal again until the power had dropped to almost zero.  Stupid!

      Of course I once designed a full custom chip for a video game company.  Two small parts I didn't design but had the silicon vendor add...an internal oscillator that had to be running but I didn't care a lot about the speed plus the power on reset generator.

      Time passes, silicon arrives.  Yep, the power on reset didn't work, it only generated a reset on power FALLING.  Also the oscillator didn't oscillate. *sigh*  At least I'd brought those pins out as test points in a way that test equipment could override them during product test.  I had to add an oscillator and reset circuit to the PC board and it did work after that.  I believe the video game people never paid the company for the silicon since they'd screwed up the part...but I stayed out of the big money lawsuits.


      On 01/26/2013 07:13 AM, Rick Sparber wrote:

      I own a ShumaTech® 350 with 550 Daughterboard plus Chinese scales. About 75% of the time that I turn on AC power to this system, my Z axis scale freezes up. This article offers a simple fix.

       

      If you are interested, please see

       

      http://rick.sparber.org/drops.pdf

       

      Your comments and questions are welcome. All of us are smarter than any one of us.

       

      For the full index of my articles, see rick.sparber.org.

       

      Rick

       

       


      -- 
      Jerry Durand, Durand Interstellar, Inc.  www.interstellar.com
      tel: +1 408 356-3886, USA toll free: 1 866 356-3886
      Skype:  jerrydurand 
      
    • Rick Sparber
      Jerry, The DRO350 is MUCH worse than you are describing. Not only is there no power control circuitry, there are two incompatible grounds. Furthermore, the
      Message 2 of 5 , Jan 26, 2013
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        Jerry,

         

        The DRO350 is MUCH worse than you are describing. Not only is there no power control circuitry, there are two incompatible grounds. Furthermore, the board is double sided with no ground plane and poor analog layout techniques. High currents flowing to the LED display generate a large voltage drop in this one thin ground trace that feeds the scales. This causes the scales to have significant jitter. At least that problem is easy to fix by moving 3 wires.

         

        The circuit that locks up is inside the slider of a scale. It started out as a 6” hand held caliper powered by a battery. You pop in the battery and it works. The problems only started when the battery was replaced by long wires feeding from a 3 terminal power supply tied to a different ground. So although the slider is the element that locks up, I really can’t blame those designers.

         

        Rick

         

        From: mill_drill@yahoogroups.com [mailto:mill_drill@yahoogroups.com] On Behalf Of Jerry Durand
        Sent: Saturday, January 26, 2013 10:22 AM
        To: mill_drill@yahoogroups.com
        Subject: Re: [mill_drill] new article:A Possible ShumaTechR 350 with 550 Daughterboard Power Up Fix

         



        I wish people would put better power on resets into boards and chips.  I ran into a problem with a TI processor I used in an industrial application, on power up no matter how slow the rise time it held itself in reset until an appropriate level was reached.  However... once the power up reset was happy with the power, it wouldn't generate a reset signal again until the power had dropped to almost zero.  Stupid!

        Of course I once designed a full custom chip for a video game company.  Two small parts I didn't design but had the silicon vendor add...an internal oscillator that had to be running but I didn't care a lot about the speed plus the power on reset generator.

        Time passes, silicon arrives.  Yep, the power on reset didn't work, it only generated a reset on power FALLING.  Also the oscillator didn't oscillate. *sigh*  At least I'd brought those pins out as test points in a way that test equipment could override them during product test.  I had to add an oscillator and reset circuit to the PC board and it did work after that.  I believe the video game people never paid the company for the silicon since they'd screwed up the part...but I stayed out of the big money lawsuits.

        On 01/26/2013 07:13 AM, Rick Sparber wrote:

        I own a ShumaTech® 350 with 550 Daughterboard plus Chinese scales. About 75% of the time that I turn on AC power to this system, my Z axis scale freezes up. This article offers a simple fix.

         

        If you are interested, please see

         

        http://rick.sparber.org/drops.pdf

         

        Your comments and questions are welcome. All of us are smarter than any one of us.

         

        For the full index of my articles, see rick.sparber.org.

         

        Rick

         

         



        -- 
        Jerry Durand, Durand Interstellar, Inc.  www.interstellar.com
        tel: +1 408 356-3886, USA toll free: 1 866 356-3886
        Skype:  jerrydurand 




      • mr_fix
        What can I say Rick, you continue to amaze me. I m about to install my DRO 350 and don t know if that will be a problem that I run into but if it is I have
        Message 3 of 5 , Jan 26, 2013
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          What can I say Rick, you continue to amaze me. I'm about to install my DRO 350 and don't know if that will be a problem that I run into but if it is I have the answer.

          Thanks for all your research and problem solving!
          Keith

          --- In mill_drill@yahoogroups.com, Jerry Durand wrote:
          >
          > I wish people would put better power on resets into boards and chips. I
          > ran into a problem with a TI processor I used in an industrial
          > application, on power up no matter how slow the rise time it held itself
          > in reset until an appropriate level was reached. However... once the
          > power up reset was happy with the power, it wouldn't generate a reset
          > signal again until the power had dropped to almost zero. Stupid!
          >
          > Of course I once designed a full custom chip for a video game company.
          > Two small parts I didn't design but had the silicon vendor add...an
          > internal oscillator that had to be running but I didn't care a lot about
          > the speed plus the power on reset generator.
          >
          > Time passes, silicon arrives. Yep, the power on reset didn't work, it
          > only generated a reset on power FALLING. Also the oscillator didn't
          > oscillate. *sigh* At least I'd brought those pins out as test points in
          > a way that test equipment could override them during product test. I
          > had to add an oscillator and reset circuit to the PC board and it did
          > work after that. I believe the video game people never paid the company
          > for the silicon since they'd screwed up the part...but I stayed out of
          > the big money lawsuits.
          >
          >
          > On 01/26/2013 07:13 AM, Rick Sparber wrote:
          > >
          > >
          > > I own a ShumaTech® 350 with 550 Daughterboard plus Chinese scales.
          > > About 75% of the time that I turn on AC power to this system, my Z
          > > axis scale freezes up. This article offers a simple fix.
          > >
          > >
          > >
          > > If you are interested, please see
          > >
          > >
          > >
          > > http://rick.sparber.org/drops.pdf
          > >
          > >
          > >
          > > Your comments and questions are welcome. All of us are smarter than
          > > any one of us.
          > >
          > >
          > >
          > > For the full index of my articles, see rick.sparber.org.
          > >
          > >
          > >
          > > Rick
          > >
          > >
          > >
          > >
          > >
          > >
          > >
          > >
          >
          > --
          > Jerry Durand, Durand Interstellar, Inc. www.interstellar.com
          > tel: +1 408 356-3886, USA toll free: 1 866 356-3886
          > Skype: jerrydurand
          >
        • Rick Sparber
          Keith, I just updated the article to make it clearer. If you are new to this DRO, I do maintain an unofficial set of document on it and the 550:
          Message 4 of 5 , Jan 26, 2013
          • 0 Attachment
            Keith,

            I just updated the article to make it clearer.

            If you are new to this DRO, I do maintain an unofficial set of document on
            it and the 550:

            http://rick.sparber.org/sh.htm

            I look forward to what you find.

            Rick

            -----Original Message-----
            From: mill_drill@yahoogroups.com [mailto:mill_drill@yahoogroups.com] On
            Behalf Of mr_fix
            Sent: Saturday, January 26, 2013 5:12 PM
            To: mill_drill@yahoogroups.com
            Subject: [mill_drill] Re: new article:A Possible ShumaTechR 350 with 550
            Daughterboard Power Up Fix

            What can I say Rick, you continue to amaze me. I'm about to install my DRO
            350 and don't know if that will be a problem that I run into but if it is I
            have the answer.

            Thanks for all your research and problem solving!
            Keith

            --- In mill_drill@yahoogroups.com, Jerry Durand wrote:
            >
            > I wish people would put better power on resets into boards and chips.
            > I ran into a problem with a TI processor I used in an industrial
            > application, on power up no matter how slow the rise time it held
            > itself in reset until an appropriate level was reached. However...
            > once the power up reset was happy with the power, it wouldn't generate
            > a reset signal again until the power had dropped to almost zero. Stupid!
            >
            > Of course I once designed a full custom chip for a video game company.
            > Two small parts I didn't design but had the silicon vendor add...an
            > internal oscillator that had to be running but I didn't care a lot
            > about the speed plus the power on reset generator.
            >
            > Time passes, silicon arrives. Yep, the power on reset didn't work, it
            > only generated a reset on power FALLING. Also the oscillator didn't
            > oscillate. *sigh* At least I'd brought those pins out as test points
            > in a way that test equipment could override them during product test.
            > I had to add an oscillator and reset circuit to the PC board and it
            > did work after that. I believe the video game people never paid the
            > company for the silicon since they'd screwed up the part...but I
            > stayed out of the big money lawsuits.
            >
            >
            > On 01/26/2013 07:13 AM, Rick Sparber wrote:
            > >
            > >
            > > I own a ShumaTechR 350 with 550 Daughterboard plus Chinese scales.
            > > About 75% of the time that I turn on AC power to this system, my Z
            > > axis scale freezes up. This article offers a simple fix.
            > >
            > >
            > >
            > > If you are interested, please see
            > >
            > >
            > >
            > > http://rick.sparber.org/drops.pdf
            > >
            > >
            > >
            > > Your comments and questions are welcome. All of us are smarter than
            > > any one of us.
            > >
            > >
            > >
            > > For the full index of my articles, see rick.sparber.org.
            > >
            > >
            > >
            > > Rick
            > >
            > >
            > >
            > >
            > >
            > >
            > >
            > >
            >
            > --
            > Jerry Durand, Durand Interstellar, Inc. www.interstellar.com
            > tel: +1 408 356-3886, USA toll free: 1 866 356-3886
            > Skype: jerrydurand
            >




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