Why is the instrument reporting QUERY UNTERMINATED or ERROR -420 error when using Prologix GPIB-ETHERNET controller?
After sending a command to an attached instrument, Prologix GPIB-ETHERNET controller will address it to talk to read back the response. If the command does not generate a response (often called non-query commands), some instruments will generate the QUERY UNTERMINATED error when addressed to talk. In effect the instrument is saying, you have asked me to talk but I have nothing to say. The error is often benign and may be ignored.
