Issue reading multiple Channels in SR830 Lock-In Amplifier

[Shanz]

Greetings all,

I am a beginner to LabView and I am using it to interface with the SR830 Lock-In amplifier. I am using the SR830 drivers by Stanford Research to create a program whereby I can record the values obtained from Channel 1 (for amplitude) and Channel 2 (for phase). However, the data acquisition is very erratic and sometimes it works and sometimes it doesn't. The error messages that I get are not the same as well and varies from time to time.

I tried following the example given by Stanford Research (attached) and replicating it to work for two channels. My trial program (SR830_Trial) has also been attached. Could somebody help to see why my program would not run? Thanks a million.

[Albert.Geven]

Hi

Two suggestions

1) set your gpib card to the slowest possible speed (as far as I remember 1 micro second)

     Because the 830 is not that good at handshaking with high speed. This should not be needed but most of the time it helps.

2) you use the wait unti next ms multiple. That one is not really waiting consistently the first wait. It happens it only waits 0 ms the first time.

    in the lower half you use the wait ms that is reproducible, although it can be adding up if you loop it a few thousand times.

3) Never use a sequence frame but use error in/ error out to sequence vi's.

[Shanz]

Thank you for your reply. For your suggestions:

1) How do I set my GPIB card to the slowest speed? Is it done by changing the setting as shown in the screenshot below?

2) For the "Wait until next ms", should I then increase the time for one of the channels? For example Channel 1 has a wait time of 300ms and Channel 2 has a wait time of 200ms? Or should I remove them? I idea was that for each channel to have its own wait time so both won't miss the trigger.

3) Could you please elaborate more on the sequence frame? The reason why I didn't do it initially was because the example VI given by Stanford Research did not have it.

Thank you so much for your help.

[Albert.Geven]

Hi

The speed of the bus can be changed in MAX the measurement explorer from NI. Select the gpib interface and check the properties for busspeed. I don't have an interface available so try first.

The wait multiple should simply be replaced by the wait ms.

When vi's are connected by wires, then these wires determine the execution order. So no need for sequence frames. And using error in/ error out shows also the error result when an error happens.

[Shanz]

Thank you so much for your time.

I will do the changes as you have advised and try it with the SR830 again. I will keep you updated!

[Albert.Geven]

Hi

The only remark now is that when an error pops up at the end, very carefully read where it originated because I always have the feeling the error occurs in the last call, but it also as easy can be the first call.