In an experiment I was trying to communicate with a Lock-In SR530 and I was having a lot of trouble.
Right now I have found the solution but I want to understand what is going on.
Basically, using the NI-VISA (version 20.0) I/O Command Panel, any of the commands written on the manual didn't work, but if you write a character, any character, before the command in the command panel, then it works.
For example, to measure the Reference Frequency you have to use the "F" command, but if you write "F" in the command panel and press "Write", then the ACT indicator flashes and nothing happens, if you try to read or query with the "F" command you get a timeout error. But if you enter "QF" in the command panel and press "Query", then you get the Reference Frequency. If you write "RF" and query you also get the frequency. The same thing with "1F" or something weirder, like "ßF".
This makes me think that the amount of bits the instrument expects to get and the amount of bits the computer sends differ. But I do not know why this happens and I want to find out.
Best Regards.
