@davidjryan said in DSF 6HC Pi Disconnections over SPI:
The last change was to put two separate 24V power supplies on the machine. One is for the Duet 6HC and 3HCs, one is for all other 24V/12V/5V requirements, and the Pi is on it's standalone "wall wart" power supply.
Generally, when using more than one power supply, we recommend connecting the negative terminals (ie GND, not earth) of the power supplies together, especially in the case of mainboards and toolboards connected via CAN. This eliminates the impact of a potential difference between boards where the power supplies are not in phase, or producing slightly different voltages, which can interrupt the low voltage signals between boards.
In an SBC setup, the ribbon cable connects GND between the boards, which should mitigate any potential difference between the Duet and RPi. So check the ground on both the Duet and RPi, and between them. As you're using a wall wart power supply for the Pi, it may not have an earth, so may rely on the GND from the Duet, so check this is a solid connection. It may also help to plug the wall wart power supply into a power socket as close to the power socket used for the Duet PSU, ie not into a separate wall socket, but into the same multi-way power cable.
This should, at least, make sure that it's not a power supply or ground issue causing the errors.
Ian