SR830 Lockin-Amplifier - Difficulties to read buffer via VISA

[David Leuenberger]

Hi everybody,

I am having a hard time to read from the SR830 Lockin-Amplifier measurement buffer using the GPIB commands from the SR830 manual. I am able to communicate with the instrument (commands such as *IDN? work without any problem). I tried the official Labview driver to download the data but its not working for me.
I basically use the following sequence of commands:
- REST --> reset buffer
- OUTX1
- SEND1 --> loop mode
- SRAT13 --> 512 kB/s sampling rate
- STRT --> start sampling
...wait a few seconds
When I now query SPTS? I get "980" as an answer. e.g. there should be 980 points in the buffer.
However if I query the measurement buffer with "TRCB?1" I am not able to get the data points. Instead I get the error message:

Error -1073807339 occured at VISA Read in SR830_VISA.vi
Possible reasons: Timeout expired before operation completed.

I attached two screen shots plus the Labview program. I hope someone can help me because this is taking *lots* of time.

Thanks
David

[johnsold]

David,

I don't have an SR830 or the manual handy, but I notice that you have spaces in various places in your command strings. Sometimes before the ? and sometimes not. Does the SR830 tolerate extra spaces?

Lynn

[MissyS]

Hi David,

It looks like from your code, that each time your run the VI you change the wire on the block diagram. Is this correct? If this is the case, you are reconfiguring your instrument or telling it to send data every time the VI runs. I've modified the VI so that it has both commands in one VI. Since I do not have the manual, I'm not sure of the order of the two commands, but the idea is the same.

Let me know if this changes the behavior of the instrument. I hope this helps!

What problems were you seeing with the instrument driver? Were you using this one?

Regards,

[lau0606]

Hello everybody,

I have a SR830 Lockin-Amplifier from Satnford. I would like to read the value with a GPIB interface with a computer

I am able to communicate with the instrument (commands such as *IDN? work without any problem). I tried the official Labview driver to download the data but it’s not working for me.

I have tried to use the SR830 Visa modified.vi from here:

http://forums.ni.com/ni/board/message?board.id=170&message.id=202248

But in this case it’s also not working.

In fact my question is if someone has already a vi for this lock-in to get the display value and to visualize with labview and record a file with this value as a function of the time in a .txt format.

Thanks a lot

Laurent