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    mkellner

    @mkellner

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    Posts made by mkellner

    • RE: PLC Module

      @osmar 在 PLC Module 中说:

      @mkellner Please refer to this schematic diagram.

      Thank you for responding!

      posted in Bases
      M
      mkellner
    • RE: PLC Module

      I'm waiting for a response supplier via vendor, who assures me that the supplier says it should work as it is and that I don't need RTS. I pointed out that the ESP-IDF documentation for UART indicates that RS485 Half Duplex requires a RTS pin (https://docs.espressif.com/projects/esp-idf/en/latest/api-reference/peripherals/uart.html):

      0_1535921034241_esp-idf-uart-snip.png

      0_1535920297908_PLCModuleModule.png
      0_1535920306839_exar-sp3485-pinout.png

      I think I'm going to have to tie a wire between the DE pin on the 3485 to a free GPIO to get the functionality I need.

      Hopefully the supplier will eventually provide some official documentation or schematics. I suspect that this might be what you get.

      Is anyone from M5Stack here?

      posted in Bases
      M
      mkellner
    • RE: Ideas, helping M5Stack document stuff...

      @ajb2k3 We need schematics for the modules too, please. I'd like to see it for the PLC module.

      posted in PRODUCTS
      M
      mkellner
    • RE: PLC Module

      I note that the vendor on Amazon is responsive, but not very technical or knowledgeble about the PLC module.

      Gave me the schematic for the M5 Core, not the PLC module.

      They suggested the ILI9341 (display) RST pin is what I was looking for. No. That's not quite right.

      posted in Bases
      M
      mkellner
    • RE: PLC Module

      Looks like the 485 driver is a Exar SP3485.
      Some vendor on Alibaba claims it is max3485esa replacement.

      https://datasheet4u.com/datasheet-pdf-file/1103288/Exar/SP3485/1

      The SP3485 chip has
      Pin 1 - RO - Receiver output
      Pin 2 - RE - Receiver Output Enable Active LOW
      Pin 3 - DE - Driver Output Enable Active HIGH
      Pin 4 - DI - Driver Input
      Pin 5 - GND - Ground Connection
      Pin 6 - A - Non-Inverting Driver Output/Receiver Input
      Pin 7 - B - Inverting Driver Output/Receiver Input
      Pin 8 - Vcc - Positive Supply

      What pin is DE - Driver enable?

      Pin 1 - RO -> G16
      Pin 2 - RE -> ???
      Pin 3 - DE -> ???
      Pin 4 - DI -> G17
      Pin 5 - GND -> (output port G)
      Pin 6 - A -> (output port A)
      Pin 7 - B -> (output port B)
      Pin 8 - Vcc - 5V (?)

      Is there a schematic for the little module?

      alt text

      posted in Bases
      M
      mkellner
    • PLC Module

      I am converting a project from a raw esp32 module/MAX 485 driver -> modbus to M5Stack/PLC module.

      Does the PLC module supply power to the CPU from the 24V input?

      Is there an RTS Control line for the RS485 converter or is RTS Control automatic?

      (RTS Control is a method with which the RS232 device (typically a PC) tells an RS232-RS485 converter when it should enable its RS485 driver, i.e. when it should be transmitting. http://www.kksystems.com/rtscontrol )

      Is there a chip specification for the 485 converter? Which is used?

      posted in Bases
      M
      mkellner