Multiple TinyG boards on single PC

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  • March 9, 2016 at 10:38 am #9419
    ken.gentry
    Member

    I have a motion control project that will require 7 or 8 steppers. Can I hook up two (or more) TinyG boards to a single Windows PC and have them show up as separate COM ports?

    Thanks,
    Ken

    March 9, 2016 at 4:21 pm #9420
    ken.gentry
    Member

    Wanted to supply more details. I work for a company that makes point of sale equipment. We are attempting to automate transactions on the system and a physical credit card terminal. Our existing automation app generates click events on the register screen to purchase items. At the end of the sale we need to physically swipe a payment card and possibly answer prompts on the pin pad.

    A mechanical engineer at our company is almost finished building a desktop sized CNC machine that will move around and press keys on the pin pad. There will two more axes that will bring a card around and swipe it through the terminal’s card slot.

    The XYZ motion for the keypad will be fully independent of the card swipe XY motion.

    We will most likely add add a card carousel in the future that could be spun by a stepper and the card handling motion could coordinate with it.

    So I’m hoping we can connect two TinyG boards to the same computer then send keypress motion control to one board and card swipe motion control to the other board.

    We do not care about the two TinyG boards working together. We just need two boards to show up on separate COM ports and allow our automation app to send commands to the two boards independently.

    Budget for this is not a concern at all. Buying two TinyG boards would work for us.

    Thanks for any help.

    Ken

    March 9, 2016 at 7:18 pm #9421
    cmcgrath5035
    Moderator

    At the OS level(Win__ I assume) I see no reason why two tinyG’s would not connect simultaneously. The USB front end of tinyG is an ftdi discrete USB to serial device. So two tinyGs is really the same as two any other identical USB devices being connected , each should get a unique COMx port name.

    I don’t know enough about WIN port assignments, specifically would they always connect as COMX and COMY, repeatedly?
    In linux, udev could be used, I think, to set you computer up to always connect to a specific port based on some unique characteristic of the tinyG device (a serial number, etc). You may need to hack about a bit with this.
    You would need to inform your control program that COMX was for Keypad motion, COMY for Card swipe, for example.

    March 10, 2016 at 3:12 pm #9423
    ken.gentry
    Member

    Agreed. USB device enumeration at startup could cause swapping of the ports. I worked on an embedded Linux project with A side and B side printers. When the unit rebooted there was no guarantee the printers would come up on the correct port. Luckily we had a great working relationship with the printer manufacturer and they helped us figure out a reliable scheme to deal with this.

    Certain FTDI USB/serial devices have EEPROM where a serial number is stored. This could be sniffed and used in a manual configuration step to specify “Board A has serial number 12345” and “Board B has serial number 54321”. Then the controller could figure out which is which without much pain.

    Thanks,
    Ken

    March 10, 2016 at 9:30 pm #9424
    cmcgrath5035
    Moderator

    It is fairly straightforward to dig out those unique identifiers in Linux, and then construct udev rules to handle the day to day boots.

    I am clueless what that means for Win systems.

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