I think I have found a solution to the problem you are having. It looks like owserver is not running which is why your python script is throwing the exNoController error. I tried installing owfs and when I ran the following python script I got the same error as you.
sensorlist = ow.Sensor('/').sensorList()
for sensor in sensorlist:
To fix the problem I did the following things.
Edit /etc/owfs.conf using the command:
sudo nano /etc/owfs.conf
Add the following line in the same area as the other server:device lines:
server: device = /dev/i2c-1
This will allow owfs to connect to the 1 Wire Pi Plus.
The whole of the owfs.conf on my Raspberry Pi looked like this:
! server: server = localhost:4304
server: i2c = /dev/i2c-1:ALL
mountpoint = /mnt/1wire
http: port = 2121
ftp: port = 2120
server: port = localhost:4304
Next start the owserver with the command:
sudo /opt/owfs/bin/owserver -c /etc/owfs.conf --pid-file /var/run/owfs/owserver.pid
Once owserver is running you should be able to run your python program.
owserver will need to be started each time the Raspberry Pi boots. The easiest way to do this is to add the above command into /etc/rc.local so it will be run when the Raspberry Pi starts.