Capture E4406 EVM measuremen​t screen

Question

Hi distinguished NI engineers,
           Nowadays , I attemps to setup EVM test in our lab. All seems ok except screen capture problem.From the E4406 programming manual ,this insturment supports screen capture functionality.
           This commands says it would provide a view of numeric results and a ploar constellation graph in the two windows.How i can realize that in labview, my experience for this is limited.
          Could anyone raise me a hand? Thanks.
Attachments:
schematic.JPG ‏23 KB
COMMAND.JPG ‏36 KB

Answer 1

Hi Dennis,
                Sorry for reply late. I will clarify something~~
You seem to be asking a couple different
questions. First, does the command work? I mean, does the screen change
to reflect what you want?
(The command really work.)
Second, you are doing a read but you haven't issued any command to
the instrument to send any data. You would need to issue a query (i.e.
something with a '?' at the end.
(I have already configured the command"DISPlay:EEVM CONStln" to the VISA write. Do you mean i still need to issue the command to Visa Read before get the expected graph?)
Third, you mention a screen capture but you are not issuing any
command that tells the instrument to perform such an operation. That's
a command you will have to look up and then find the command to
transfer it to the pc.
(I already issue the command"DISPlay:EEVM CONStln" command to perform the command and also configure the measurment before display the screen.I was a bit lost.What kind of command you think i need to put it into? Because i think the sequence is clear:configure the measurment-->conduct the measurement-->capture and display the result.)
Fourth, when you finally do issue a query and do a read, you will
have to convert the string returned into numeric data before it can be
displayed on a graph.
(Yes ,I'll remember this rule to get the graph.)
Fifth, a LabVIEW graph will not correctly display a polar plot. You
will probably have to use the picture indicator to display this. Look
at the shipping examples. Do a search for 'polar'. You may be able to
do a normal trace on the instrument, fetch that, and display the data
in LabVIEW without setting up the instrument to do it. I suspect this
will be faster than setting up the instrument, doing a capture,
transfering the capture, and then converting the capture to be
displayed in LabVIEW.
(All i want is to capture the whole measurment screen, Do you think it make sense?Maybe i do not care whether it's a polar plot or other kind of graph.)
           Thanks a lot for your replay and patience.
Evan