Ethernet control DMM6500 problem

I don't immediately see a problem here. I just remember that Keithley devices are for some reason a real pain in the a** to program. One thing not in the right order and the device refuses cooperation. It might be that you first have to reset the device once (sending *RST) before modifying settings, or maybe you need to first set the correct measurement mode (e.g., :SENS:FUNC "VOLT:DC"). I also never send the first colon (:) for any command and it works fine. Just keep trying with different examples from the manual until you get some reaction.

When you post code, copy the code and use the Insert Code Snippet option to insert it into your posting. That gives it standard Igor coloring, and also makes it possible to copy and paste into Igor. Folks reading your code may be able to try it out and suggest useful updates. You will usually get more useful answers that way.

It is common to paste code straight into the posting; if you do that, one of us admin types will often patch it up for you. But in this case, it would require a lot of typing :)

The first parameter to viWrite and viRead is a session identifier returned by viOpen. See the documentation for viOpen for an example.

If you have a global string variable named ud_dmm6500 that contains a session identifier returned by viOpen then your Read_DMM6400_1 looks OK in so far as that parameter is concerned.

This

is equivalent to this

so there is no need to use $.

Also, this makes no sense:

Use this instead:

Putting it all together:

But I'm not sure that is right either.

Does the instrument expect to receive a terminator such as LF or CRLF?

Does the instrument send a terminator such as LF or CRLF? Ethernet does not have an END signal like GPIB so it may try to read 1024 bytes and hang until it times out. You might be better off using VISAWrite and VISARead. The latter automatically ends when the terminator character is received.

Quote:

Picture two shows that I use SCPI to set a current range it doesn't work.

It would be useful to know exactly what is going wrong. If you are getting an error, what is the error message?
 

Replay for chozo

Thanks for your suggestion I will try it.

hrodstein wrote:

Also, this makes no sense:

Variable length = strlen(com_str)        // What is com_str?
viWrite(uuu, "READ?", length, retCnt)

It's a mistake copy just ignore it

hrodstein wrote:

Does the instrument send a terminator such as LF or CRLF? 

I'm not sure about that. Maybe try VISAWrite and VISARead is a good choice.

hrodstein wrote:

It would be useful to know exactly what is going wrong. If you are getting an error, what is the error message?

When I use GPIB to set a current range it will change the unit on DMM6500 like the picture below.

It didn't work with ethernet. But the Read? command worked it will return a voltage from DMM6500.

Thanks for everyone's reply. I'm new here and also new to foreign forums. If I have something wrong let me know it. 

The SCPI documentation for the DMM 6550 says:

Quote:

A command string sent to the instrument must terminate with a <new line> character.

I suspect that it also transmits an <new line> character (LF) when it sends a reply.

Also, it shows the read command as ":READ?", not "READ".

I would try this:

hrodstein wrote:

The SCPI documentation for the DMM 6550 says ......

I will try it later.