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Switching Led

Discussion in 'General Electronics Chat' started by willeng, Jul 4, 2014.

  1. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

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    Internet is 1/2 up. I'm connected direct to my "backup" modem.

    Next, I need to check out wireless.
     
  2. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

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    Wireless is up, but I have some things to fix.
     
  3. willeng

    willeng Member

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    Deleted Post!
     
    Last edited: Jan 27, 2016
  4. dave

    Dave New Member

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  5. willeng

    willeng Member

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    Hi Kiss,
    Didn't know if you wanted to continue or not as I didn't get any replies to some previous questions?

    Anyway, I have to wait until next week when we go to the big smoke to get the appropriate circuit breaker & switches etc to wire this all in safely into the test bench.
    I have been attempting a sketch that gives me easy control of the setpoints, ramp etc.
    I also wanted to be able to Pause at any point or points of interest & incrementally step up or down for fine precision adjustments to pause exactly on the particular point of interest.
    Thinking about it now HOLD would be a better word than Pause.

    I have spent considerable time trying to nut this out properly & I have finally come up with something that is working not to bad, I think?
    As it turns out, it is also a stand alone controller for some other things without PID & it can be adjusted to work very fast indeed.


    Cheers
     
    Last edited: Jan 31, 2016
  6. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

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    I thought you were playing with the new software and I was playing in the snow among other things like broken Internet.
    Two days in a row were doctor appts and errands for me an mom.

    What questions are open?
     
  7. willeng

    willeng Member

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    Hi Kiss,
    Yes, I am intrigued now with this software, just a couple of things before I get back to some previous questions.

    Could you have a look at my setpoint control & see if I am on the right track or have missed anything that I am unaware of.
    Here's a very short clip with an explanation at the beginning & how it works after that.
    On my computer I have to set the clip for HD to view it correctly.

    Edit; Video Removed

    What do you think, do you foresee any issues that I need to fix?

    Cheers
     
    Last edited: Feb 1, 2016
  8. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

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    I''m not sure what I'm looking at, but if it meets your needs, it's fine.
     
  9. willeng

    willeng Member

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    Hi Kiss,
    Not a problem, it is all working very nicely.

    I do not want to do this but rather get an understanding of something I have wondered about for a while.
    In the AN467 pdf - Attached, figure 12 they have the line voltage connected to the +5VDc into the microcontroller.
    How does that work?
    I may have this wrong?
    I see that you would have a DC offset on the line voltage of 5V but if the series resistance was not high enough in the microcontroller or the 5V Dc supply the current would fry everything, wouldn't it?

    If you have some time could you give me an explanation of how things actually work when connecting higher AC voltages to much smaller Dc supplies & microcontrollers.

    Also in the same figure 12, is that window comparator wired correctly, I am not questioning NXP rather than my own ignorance ?

    Hope everything worked out ok at the doctors for you both.

    Cheers
     

    Attached Files:

  10. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

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    Look at figure 15. There they derive a mains supply. The fact that the controller required little current, it;s easy to create a zener regulated non-isolated supply from the mains. That's part of the equation. That +5 is derived from the mains.

    The other part of the equation, you have seen before. Many chips have input voltages fro Vdd+0.3 and Vss-0.3 V AND the diodes have a max current associated with them. These same specs apply to some OP amps as well.

    When Vdd is 0, such as a power off condition, that normal 5V input can't be tolerated anymore UNLESS a current limiting resistor is used.

    Figure 9 has a 1 meg resistor in series with the input. So, like they say, current kills.

    Because of the IC construction, diodes exist at the pins. A metal-semiconductor junction is known as a Schottky diode. https://en.wikipedia.org/wiki/Schottky_diode Sometimes they are intensionally added: e.g. ESD diodes. See http://www.mouser.com/pdfdocs/Littelfuse_ESD_Protection_Design_Guidepdf.PDF
     
    Last edited: Feb 1, 2016
  11. willeng

    willeng Member

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    Hi Kiss,
    Thanks for that, I will have a look at what you mentioned, interesting!
    Yes current can kill, everything!

    Ok, you mentioned a while back that for a buffer you can use a "nice single supply Opamp".

    Is the NE5534 a good choice for this application, I have some already.


    Cheers
     
  12. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

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    • Like Like x 1
  13. willeng

    willeng Member

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    Hi Kiss,
    Thanks for that, I will see where I can source some from.
    At this stage it looks like I will have the circuit breaker & switches I need at the end of this week, I will set it up in an enclosure & post some pics when done.
    I need to study up on some things you have written, so instead of asking more questions I'll try to get a handle on what is present.
    Cheers.
     
  14. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

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    The newer op amps dont come in DIP packages. SMT to SIP and DIP adapters are available.

    I think I mentioned proto-advantage in Canada, who will procure a digikey p/n and mount it on their adapters.

    My creiteria was low offset, rail to rail, single supply, low GBW product and unity gain stable.
     
  15. willeng

    willeng Member

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    Hi Kiss,
    Thanks for that, I was unaware that the adapters you mentioned were available & I have not looked at SMT components due to the size of the them & difficulty of trying to solder the things.
    I will look into a few things today & see what I can come up with.

    Cheers
     

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