Mervis & Stepper motor

  • Is it possible to control from Mervis a Stepper motor, and if yes whats the recommended way of doing it, Modbus, I²C?

    I want to control 4 small stepper motors.

  • administrators

    How do you physically want to drive them?

  • @tomas_hora
    Sorry, I did not see your reply, so I was thinking it could not be done.

    Here is what I wane do:

    I wane use the UniPi also as a feeding computer, that can control the amount plant nutrients, in our greenhouse.

    I wane control 5 peristaltic pumps with 12v Steppermotors, 1 big peristaltic pump, that pumps 5 ~ 900 ml/min water, and 4 small peristaltic pumps 0 ~ 25 ml/min, that add the nutrients to the water (I need to ad 0.25 to 3ml/L of different type of nutrients), where they get mixed and then distributed by hoses and controlled solenoid valves to the plants.

    Peristaltic pump:
    alt text

    I would like use this board to drive the stepper motors, as it is a very affordable solution.
    And it comes whit this software to control the stepper controller, but it I think that software is not easily gone work whit UniPi.

    With most other solution is also using a Windows driver, so I am up for any other controller solution, if you have any affordable recommendations, I only need to control the rpm's, the 4 small pumps uses 0.75A and the big one 1.8A with both in a 12 or 24V current version.

    Is there a way to this with MERVIS, or one with one of the other software solutions supported by UniPi?

    For information, here is what I also wane do with the UniPi for determining the best software solution:

    I also wane measure the soil moister content whit this sensor, to adjust the amount of watering.
    (there is also a RS485 version for if I wane use L503 Neuron, and the maker is also thinking/developing a 1wire version)

    Next, to that, I wane control some relays, led drivers and a fan, both with 0~10V, and 1wire U1WTVS and a temp sensor for the water temperature.

    I also wane make a weekly feeding schedule, where the amount and/or type of nutrients gets auto adjusted as the vegetables grow.

  • administrators

    Hello @Havor,

    you cannot implement such boards in Mervis. I suggest using Modbus (RS485 or TCP) devices because implementation in Mervis is really easy.

    A weekly schedule is also a function block of Mervis.

    I cannot tell much about the other SW solutions as we do not have much experience with them....

  • @tomas_hora
    Hi Tomas

    What type of controller works best with Mervis? 1 on 1 direct steering, semi-direct or pre-programmed?

    Would something like this Mitsubishi PLC work in slave mode, and would it be more or less plug and play in Mervis, or would I need a other solution?

    I think that I would have no real problems whit Mervis itself, but if setting up requires a high-level knowledge of protocols it will get hard for me.

  • Hi @tomas_hora

    Any answers/suggestions on what type of controller I should use?

  • administrators

    @Havor I do not have any experience with Stepper motors connected via Modbus so I cannot tell... But implementing any TCP or RS485 Modbus device is pretty straight forward in Mervis. You just need to map the registers you wish to read from/write to the Modbus device...

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