Can write data from network analyser but cannot read it (SCPI commands)

Hi guys,

I'm trying to read the currently set value from an Agilent E5071C network analyser (ENA), using a TCPI/IP connection method.

As one example of a SCPI command I've tried for setting the start frequency:

The below command works for setting the start frequency:

:SENSe{[1]-160}:FREQuency:STARt <numeric>

The below command should return the currently set frequency:

:SENSe{[1]-160}:FREQuency:STARt?

I've used the Matlab code below to set the start frequency to 1GHz, which works:

fprintf(agilentENA, [':SENS:FREQ:STAR 1e9'])

But when I try to query it with the below code, I just receive an error:

fprintf(agilentENA,':SENS:FREQ:STAR?');
out = str2double(fgets(agilentENA));

The error I receive is:

Warning: Unsuccessful read: A timeout occurred before the Terminator was reached.

I've tried increasing the timeout to 100 too, but it still shows the same error message. It's odd how I can write to the instrument, but cannot read to it.

Thanks in advance for any support.

Best Regards, Charlie

Answer 1

[Longhao Wu]

You need to know the channel num.