Some additional information, since I had time. I flashed a new sd card with a brand new raspbian stretch lite image (latest version, 2017-11-29)

installed git and updated the system

sudo -s
apt-get install git
apt-get update && apt-get upgrade -y && apt-get dist-upgrade -y
raspi-config and changed the hostname

Then installed the latest evok version (from commit 8a14c95 it seems).

• Selected website port 80
• Internal API port 8080
• Install for Unipi Neuron (I have the S103)
• No WiFi
• Reboot

And this time it works... I don't know if this is due to something that was changed in the last commit (between 11am and 1.30pm today) or simply not installing the gpiozero library.

Hi,

Sorry to hijack this thread a little, but it seems that I have a very similar problem, so maybe this can help both of us?
I get the same empty web interface, but I'm not using Codesys as far as I know.

I started with a bare install of Raspbian stretch lite, installed a few basic things

apt-get install git vim supervisor python-gpiozero

Then followed the installation instructions from the evok git repository.

I get the same error:

$ tail /var/log/evok.log

2018-01-24 11:03:13,781 - evok - ERROR - 'NoneType' object has no attribute 'do_scan'
Traceback (most recent call last):
  File "/opt/evok/neuron.py", line 225, in scan_boards
    yield self.modbus_cache_map.do_scan()
AttributeError: 'NoneType' object has no attribute 'do_scan'
2018-01-24 11:03:14,283 - evok - ERROR - 'NoneType' object has no attribute 'do_scan'
Traceback (most recent call last):
  File "/opt/evok/neuron.py", line 225, in scan_boards
    yield self.modbus_cache_map.do_scan()
AttributeError: 'NoneType' object has no attribute 'do_scan'

status looks ok to me :

$ systemctl status evok

● evok.service - Evok Modbus/Websocket/Rpc Server
   Loaded: loaded (/etc/systemd/system/evok.service; enabled; vendor preset: enabled)
   Active: active (running) since Wed 2018-01-24 11:03:18 UTC; 3min 50s ago
 Main PID: 340 (python)
   CGroup: /system.slice/evok.service
           ├─340 /usr/bin/python /opt/evok/evok.py
           └─464 /usr/bin/python /opt/evok/evok.py

Jan 24 11:03:44 unipi01 OWFS[464]: DEFAULT: ow_reconnect.c:(72) DS2482-100 bus master reconnected
Jan 24 11:04:11 unipi01 OWFS[464]: DEFAULT: ow_reconnect.c:(72) DS2482-100 bus master reconnected

Here are the open ports:

$ netstat -le
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       User       Inode
tcp        0      0 0.0.0.0:ssh             0.0.0.0:*               LISTEN      root       12789
tcp        0      0 0.0.0.0:502             0.0.0.0:*               LISTEN      root       9194
tcp        0      0 0.0.0.0:http            0.0.0.0:*               LISTEN      root       12806
tcp        0      0 0.0.0.0:http-alt        0.0.0.0:*               LISTEN      root       10395
tcp6       0      0 [::]:ssh                [::]:*                  LISTEN      root       12791
tcp6       0      0 [::]:http-alt           [::]:*                  LISTEN      root       10396
udp        0      0 0.0.0.0:mdns            0.0.0.0:*                           avahi      10357
udp        0      0 0.0.0.0:51138           0.0.0.0:*                           avahi      10359
udp        0      0 0.0.0.0:bootpc          0.0.0.0:*                           root       9499
udp6       0      0 [::]:mdns               [::]:*                              avahi      10358
udp6       0      0 [::]:56078              [::]:*                              avahi      10360
raw6       0      0 [::]:ipv6-icmp          [::]:*                  7           root       9502
Active UNIX domain sockets (only servers)
Proto RefCnt Flags       Type       State         I-Node   Path
unix  2      [ ACC ]     STREAM     LISTENING     11523    /run/user/1000/systemd/private
unix  2      [ ACC ]     STREAM     LISTENING     12867    /tmp/tmux-1000/default
unix  2      [ ACC ]     STREAM     LISTENING     11528    /run/user/1000/gnupg/S.gpg-agent
unix  2      [ ACC ]     STREAM     LISTENING     11531    /run/user/1000/gnupg/S.gpg-agent.ssh
unix  2      [ ACC ]     STREAM     LISTENING     11533    /run/user/1000/gnupg/S.gpg-agent.extra
unix  2      [ ACC ]     STREAM     LISTENING     11535    /run/user/1000/gnupg/S.gpg-agent.browser
unix  2      [ ACC ]     STREAM     LISTENING     10769    /var/run/supervisor.sock.530
unix  2      [ ACC ]     STREAM     LISTENING     9275     /var/run/avahi-daemon/socket
unix  2      [ ACC ]     STREAM     LISTENING     9278     /var/run/dbus/system_bus_socket
unix  2      [ ACC ]     STREAM     LISTENING     9281     /run/thd.socket
unix  2      [ ACC ]     STREAM     LISTENING     9399     /var/run/dhcpcd.sock
unix  2      [ ACC ]     STREAM     LISTENING     9401     /var/run/dhcpcd.unpriv.sock
unix  2      [ ACC ]     STREAM     LISTENING     6355     /run/systemd/private
unix  2      [ ACC ]     SEQPACKET  LISTENING     6369     /run/udev/control
unix  2      [ ACC ]     STREAM     LISTENING     6372     /run/systemd/fsck.progress
unix  2      [ ACC ]     STREAM     LISTENING     6375     /run/systemd/journal/stdout

Rebooting and restarting evok (via sudo service evok restart) doesn't help.