Activity Forums Questions & Troubleshooting Hardware Controllino MEGA – Irregular Resets

  • Controllino MEGA – Irregular Resets

     Jarda updated 1 year ago 2 Members · 4 Posts
  • fragglecam

    June 2, 2020 at 2:40 pm


    I’m using a Controllino MEGA in a HeatingControl Szenario with several Pumps, Vents and a lot of OneWire Temp-Sensors.

    Except of the Temp-Sensors everything is controlled by 24V (Inputs/Outputs) or 230V (Relay Block B) – Block A is not used so far.

    The 20 OneWire Sensors (DS18B20) are connected in 5 Buses to the PinHeaders (Arduino Pins 10,16,17,20,21), as their signal is 5V based !

    Since the installation there were irregular Resets of the Controllino.

    After a lot of research I found out that it was a combination between two issues:

      • The /Reset-Pin (Pin 11 on X1 and X2) has only 3,7 V ! It should be pulled up to 5 V – isn’t it ?

        I measured the Short-current (ResetPin against GND) of 0,6 mA – which means there is a Pullup of about 7k present !

        Is there any other circuit connected to the reset pin, which can bring the voltage down ?



      • There are some interferences coming from the 1-Wire buses – These finally triggered the reset from time to time.


    After knowing all that, I pushed the /Reset with another external 1k Resistor to 5V, and the Resets have gone !

    But this is not the solution ! Any ideas ?


  • Jarda

    June 3, 2020 at 11:15 am

    Dear Frank,

    Please use the solution with External 1 kOhm resistor.

    There is no risk of damage of the CONTROLLINO.



  • fragglecam

    June 3, 2020 at 12:13 pm

    Hi Jarda,

    thanks for your reply, but could you please explain, how this could be ?

    What kind of circuit is in there that cause this voltage drop – or is it defective ?

    On my other Units (MINI and MAXI Automation) I have full 5V in the /RESET Pin !

    Unfortunately I don’t have another MEGA here to check that …


  • Jarda

    June 4, 2020 at 12:23 pm

    Dear Frank,

    your CONTROLLINO is not destroyed and this is behaviour of the MEGA variant only due to the connection of more ICs to /Reset line (higher current consumption via pull-up).

    With this configuration we have passed EMC imunity test, but we are going to improve it in the next production lot.

    Thank you for your feedback.



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