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issues with BS2P setup when serial cable is removed? — Parallax Forums

issues with BS2P setup when serial cable is removed?

l8_apex_itl8_apex_it Posts: 16
edited 2009-08-08 00:31 in BASIC Stamp
I have an application which is working fine when the laptop with the serial cable is connected. If it matters I have the serial plugged directly to a breadboard with the stamp. I went to unplug it to perform an installation / qualification of the new setup. At the point I disconnected it I heard a solenoid disengage. With out the computer hooked up to the BS2P it appears as thought the setup is not working evident by a SSR relay disengaging. I do have debug commands through out the program. Do I need to comment the debug commands out to run stand alone? Could there be some other issue. I haven't run into this before although I haven't used the debug much before either.

For what it is worth - This application utilizes two ADC0831's, and a SSR. I am using Pin# 0,1,2, and 3 to communicate with the ADC0831's.

Comments

  • dev/nulldev/null Posts: 381
    edited 2009-08-07 17:49
    Can you provide a schematic? Do you have a protecting diode on the SSR's inputs?

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    Don't worry. Be happy
  • l8_apex_itl8_apex_it Posts: 16
    edited 2009-08-07 18:15
    No, I don't have a schematic at this time. (That is my next project.) I don't have a protecting diode although I have a 1k resistor to limit current to protect the stamp and SSR.. Based on the question I'm assuming I should have a protecting diode in addition to the resistor?

    I did verify earlier that I had 5v at the cable going to the SSR. As soon as I would disconnect the serial cable from the laptop, the voltage would drop instantly.

    Post Edited (l8_apex_it) : 8/7/2009 6:42:22 PM GMT
  • FranklinFranklin Posts: 4,747
    edited 2009-08-07 21:01
    are your grounds tied together? That schematic or at least a drawing would help as your problem seems to be in the wiring.

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    - Stephen
  • l8_apex_itl8_apex_it Posts: 16
    edited 2009-08-07 22:49
    I have the serial connector exactly like this image. Although, I grabbed a cable a co-worker modified for programming it when I am in the clean room with my laptop (connected straight into the serial port of the laptop). I need to verify 6&7 of the PC are jumpered and 2-5 are in the correct order at the BS2P. When I work program it at my desktop I am using the parallax USB to serial adapter and a cable I made. I did verify again that at my desk it doesn't misbehave when I unplug the serial cable. When I went back into the clean room I updated to 2.4.2 of the software and tried it again. Sure enough, as soon as I disconnect it, the system misbehaves. If I power cycle the application w/o a serial connection it appears to return to normal operation.

    * Although, I do have pins#4 and #23 sharing the same ground. I've done this on most of my projects for some reason and don't ever remember having an issue before. Is this a bad practice? Could this explain the behavior I am seeing?

    * I should have mentioned that I am using a DC/AC SSR. 5volts off of the BS2P with a 1k resistor. Due to it being a DC/AC resistor I don't belive I need the protecting diode correct?

    thanks for the input. Since I need to document it anyway I will work on getting some schematics together.
    basic stamp bs2 serial port schematic.gif
    254 x 134 - 6K
  • FranklinFranklin Posts: 4,747
    edited 2009-08-08 00:31
    You can delete your OOPS by clicking the red X in the upper right corner.

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    - Stephen
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