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Zero crossing detection for a battery spot welding machine with what parts should be used — Parallax Forums

Zero crossing detection for a battery spot welding machine with what parts should be used

I have two questions about this

What micro controller would you use and why

Are there any code examples for this type of application for the micro controller you are suggesting

Here is basically what I would like to be able to with this knowledge

I would like to control a battery welding transformer at low to high amperage output on the secondary winding circuit ( I just need a code example for this particular part )

I would also like to be able to control the amount of time the transformer has power to the primary coil
Depending on which micro controller you tell me I would have some experience doing this part maybe ?

Because the micro controller that controls battery welding machines are crap because you will be lucky if they will last a year with minimum use

The most common failure of these units are as follows

No function control to trigger the transformer output but the controller power on and boots up
Or
It sometimes trigger the transformer output but unpredictable weather it works or not
Or
Does not power on and dose not boot up but has power to the micro controller
Or
The controller power on but controller screen is blank or is scrambled and can not make sense of what is on the screen
Or
The functionality of them are not concise enough to be reliable and your welds suffer from this issue so you have to keep redoing them until get good results ( will lead to controller failure eventually )

The only thing that is not a real big deal is the cost of these controller boards are not very expensive less than $40.00 for a controller that has a lot features on it
Less for controllers that have less features on it

But they all have the same problem that they do not last long

So I am getting to point that I am looking into building one of them and see if it would last longer
This is because I saw this post that got me to ask these questions about how this might be done

Comments

  • Peter JakackiPeter Jakacki Posts: 10,050
    edited 2021-01-19 00:34
    You have the information, you have the questions. We have the questions, but we do not have the information.
    Drawings, diagrams, schematics, photos, links. Number 5 needs more input. More input! More input! The more, the better.

    btw, I doubt that the microcontroller is cr** but the overall design might not take into account the large amounts of EM energy being induced throughout the circuit. If it is built to a price then that will compromise the design. The actual micro used is not really relevant although it should be a single-chip with Flash and preferably internal runtime oscillator (not just for booting). The smaller the chip the better IMO and those like the EFM8 parts I use certainly fit the bill but then again, another might be more suitable etc.

  • kwinnkwinn Posts: 8,684
    @sam_sam_sam

    What Peter posted!


  • jmgjmg Posts: 14,595
    I would also like to be able to control the amount of time the transformer has power to the primary coil
    Depending on which micro controller you tell me I would have some experience doing this part maybe ?

    Because the micro controller that controls battery welding machines are crap because you will be lucky if they will last a year with minimum use

    The most common failure of these units are as follows
    .....
    So I am getting to point that I am looking into building one of them and see if it would last longer
    The MCU chosen is secondary, many other design elements are more important.

    Energize time is essential a fairly simple timing pulse problem, but keep in mind the Welder curves often include :

    * Welder Current
    * Welder Voltage
    * Welding pressure
    * Welding displacement

    and those all need fast analog measurements.

    and you may need to decide if AC fractional cycle control is needed, or if DC (lower ripple current) is needed.
    You could also choose primary side (eg triac/SCR) or secondary side (MOSFET) controls.

    Welders have larger energies around, so reliable design needs special care & a watchdog is probably a good idea.
  • GenetixGenetix Posts: 1,500
    sam_sam_sam,

    How does production test the welds?

    At one company I worked for, production would place the welded parts in a torque tester, and at another they pull tested 5 samples before running.
  • Trying to pull the tabs off of the battery terminals by hand
  • sam_sam_samsam_sam_sam Posts: 2,239
    edited 2021-01-27 13:21

    I have more or less have decided to do something like this that in figure number 3 and 4



    And use some of the code that is below


    https://forums.parallax.com/discussion/76898/controlling-120-vac-lights-with-a-stamp

  • I need to get all the parts together and get it to work

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