Shutdown not working

This is the same with the emonTx, emonTH and the emonPi. From the FAQ:

Q: My emonTx / emonTH / emonPi won’t read the new sensor that I just plugged in. How do I fix it?

  • Power down and power up again.

    Almost all of the sensors attached to an emon sensor node (emonPi, emonTx, emonTH) need to be present at power-up, else they will be ignored.
    The sensors are handled by the Atmel 328P inside the same enclosure as - but independent of - the Raspberry Pi. So rebooting only the Raspberry Pi will not resolve the issue. Powering off, then on again, resets the 328.