Arduino Forum

Using Arduino => Installation & Troubleshooting => Topic started by: a-agarwal on Jun 19, 2018, 12:02 am

Title: Over/under voltage faults
Post by: a-agarwal on Jun 19, 2018, 12:02 am
I am using an Arduino UNO (rev3) and AdaFruit MAX31856 ( board to monitor thermocouple temperature. The thermocouple Arduino UNO board is powered externally via a 12VDC (0.5 A) power supply (2.1mm jack). It is connected to our work laptop via a USB-hub (self-powered). Three other USB connections to two separate Arduino boards (UNO and Mega250), and an Arcus motor controller are also on the USB-hub.

When I initiate the thermocouple software, while all the aforementioned peripherals are connected, we often see an "Over/under voltage fault" appear. This causes the thermocouple to either read 0 deg C, or read the same temperature each time we probe it.

I've only been able to find two fixes to prevent the fault from occurring: (1) connect the thermocouple Arduino UNO and AdaFruit board to a separate computer altogether, which is manageable but also annoying in terms of copying collected data via USB flashdrive. Or, (2) disconnect the three other USB peripheral connections, but we ideally need to control all these boards at the same time.

I'd like to understand why I'm seeing this fault, and what are alternate solution(s) to fixing it. Thanks.

Title: Re: Over/under voltage faults
Post by: sterretje on Jun 19, 2018, 05:49 am
Where does "Over/under voltage fault" appear? On the PC. I'm not sure if a hub can report this to a PC, but either your PC or the hub can't deliver enough power. Time for a second hub?

Does your motor controller have its own power supply?