Troubleshooting Tips

  • Log files for the various PyHK subsystems can be found in /var/log/pyhk/.

  • If you are getting an Internal Server Error page when attempting to access the website, this typically indicates an invalid pyhkweb configuration file or a missing depenedency. Check the error messages recorded in /var/log/apache2/error.log for further information.

  • If you can’t reach the website at all (or if you need local access and do not have an internet connection), try going to http://127.0.0.1 from a web browser on the machine running PyHK. Note that if https is enabled (recommended), your web browser will complain about security issues; this is expected, since 127.0.0.1 is not the name the TLS certificate is assigned to. You must tell the browser to ignore or proceed anyway. If you see this security warning at your normal subdomain (often __.pyhk.net), your TLS certificate has likely expired and should be renewed (see the certbot instructions to renew it). If you can access PyHK from http://127.0.0.1 on the local machine but not from your subdomain on an external machine, check that your subdomain is pointing to your current IP address and that there are no firewalls or routers blocking port 80 and 443.

  • If pyhkd or pyhkweb fails to start, double check your JSON5 config files. Online JSON5 validators can be very helpful here (as of writing, one can be found at https://jsonformatter.org/json5-validator). The JSON5 command line interface (not installed by default, instructions available at json5.org) also contains a syntax validator (json5 -v <file>). Finally, since valid JSON is always valid JSON5, any of the many online plain JSON validators can check for common syntax errors if you remove JSON5-specific features (such as comments).

  • If you consistently get an error about a serial device being busy, and the issue persists after rebooting, it may be that modemmanager is taking control of the device. Try removing it (sudo apt-get purge modemmanager).

  • If the whole GPIB bus seems to be nonfunctional even after restarting PyHK and the Prologix device, it is likely one of the devices on the bus is misbehaving (often an Agilent power supply in my experience). Stop PyHK and power cycle ALL devices connected to the GPIB bus, then restart PyHK. (A script located at tools/gpibcheck attempts to identify if this state has occured, and can only be run if pyhkd is stopped.)

  • The GPIB standard places limitations on how many devices can be powered off while connected to the bus. It is best for all connected devices to be powered on, even if you don’t communicate with them or indicate their presence to PyHK.

  • If a particular GPIB device does not respond, verify the GPIB address is correct and that the GPIB cable is good. A script located at tools/gpibcheck will print all of the identity strings for devices on a working bus (and can only be run if pyhkd is stopped).