Multi channel data collection with single sweep

[Radio Bin]

We are using hp_875x device driver to program the 8720ES Network Analyzer.
It works fine when we do single channel data collection.

Now we are trying to collect data from channel 1 and 4 with one sweep.
The data collection for channel is fine.
Then we set "HOLD" for
Then we use "hp875x_channelselect" to switch active channel from 1 to 4.
The display data in channel 1 got changed.
It looks like the analyzer does sweep again.

Could you please let me know if you know how to solve this problem?
Thank you very much

[JohnM 64]

Hi Radio,

I am not very familiar with the 8720ES, but I do want to probe a little further and see if I can help all the same. Is the HOLD setting a command for the device, or a setting for the graph in CVI to keep the data displayed?

Also, are you trying to sample from channels 1 and 4 at the exact same time? Or are you trying to collect and display channel 1, keep that data on the screen, and then add to that a new sweep of channel 4?

john m
Applications Engineer

[Radio Bin]

The "hold" is for the device 8720ES.
We do need sample from channels 1 and 4 at same time.
Thank you very much for your help.

[JohnM 64]

Hi Radio,

I searched the instrument driver network for your device, and only found drivers for LabVIEW 6.0 and 7.0. Is the driver you have for CVI? If so, where did you get the driver?

I went ahead and installed the LabVIEW 7.0 driver just to hunt around in the context help and see what I could find, even though I am not familiar with the device. I did not find a Hold command anywhere, but I did find a VI where you can set and couple channels. Perhaps coupling the channels together will allow you to read in both at the same time?

Someone with experience with this device may be able to better help with this issue. Perhaps you would have better luck finding someone who has used it by posting on the Instrument Control discussion forum. Perhaps someone who frequents that board will know better than I do how to perform this task.

john m