It would appear that you cannot reliably startup the Raspberry Pi (nnrpi1)
connected to both the USB ac mains switch *and* the USB-serial link to FEE64
console. This is because the Rly16 Service to the USB ac mains switch expects
to use /dev/ttyUSB0. However this is often assigned (at Raspberry Pi startup)
to the USB-serial link.

You can use the command 'dmesg' to observe device assignments. 

Workaround

- connect USB cable from USB ac mains witch to powered USB hub socket 
- switch off & disconnect USB-serial cable from powered USB hub socket to FEE64 console
- power up Raspberry Pi (nnrpi1)

At startup the USB ac mains switch should be assigned to the first available
device /dev/ttyUSB0 - as required.

- connect & switch on USB-serial cable from powered USB hub socket to FEE64 console

The USB-serial connection should be assigned to the next available devoce /dev/ttyUSB1 
- as required. Further instructions can be found at:

https://elog.ph.ed.ac.uk/AIDA/42