Python script for reading values from Graphtec GL840 device (see Figure 1) with PyVisa. Serves as minimum working example.

Figure 1: Graphtec GL840 in operation

The Graphtec class has been proven to work with a Graphtec GL840, and might work with other products from Graphtec since they have the same interfacing. Graphtec GL840 was connected via a ethernet hub to the computer.

• Check first if you can interface with the Graphtec by accessing the IP address in a browser. Graphtec IP can be found and changed on the device at "Menu > I/F > IP ADDRESS".
• See the manuals APS GL-Connection and Graphtec GL840
• The type of connection might be different, for me it was a Socket connection (line 13 in GL840_example.py). See types of connections at PyVisa documentation
• At start, sometimes the Graphtec does not seem to connect. Try accessing the Graphtec directly from browser (simply plug the ip address into the address bar). You should see an interface. Perhaps only one connection with the Graphtec may be open (depending on socket connection), so close the browser when you run the code. Code should work when the browser connection works, otherwise the problem lies somewhere else. See the manuals (tip 2)