parallel data acquisition from multiple HP34970A meters

[labview_beginner]

All,

I have a subroutine which scans through about 120 channels recording voltages and dumping them in an array. I use MEAS:VOLT:DC? command and supply it with a scan list.

To do this I use 2 34970A meters each with 3 20-channel 34901A cards. What I have observed is that the data collection is serial - the subroutine goes through 60 channels on the 1st meter and then goes to the 60 channels on the 2nd meter. I am using a 82357A USB/GPIB Interface for all my data collection.

My questions is there a way to collect the data from both the meters simultaneously to save the time?

The reason being I am trying to scale this subroutine from 2 meter to 11 meters and it would certainly help me if the data acquisition from all the meters is done at the same time.

Thanks in advance.

[Dennis_Knutson]

You can't retrieve data from the instruments in parallel (unless you have 2 GPIB boards) but you can certainly tell both of them to start acquiring at the same time. I don't have the manual or driver handy but you are going to have to change how you are doing things. Instead of doing a MEAS?, you will need to set both instruments up for a software trigger or use an initiate command. Provide the scan list and then send the software trigger/initiate. If my memory is correct, you can poll each to see if the scan is complete and then do a fetch of each.

[labview_beginner]

Here is what I am trying to do. But I get following two execution errors on the 34970A:

-420 : Query Unterminated

-113 : Undefined Header

Since the vi was long I am splitting the prtscrn into 2 parts:

Part 1:

Part 2:

Since I have never used the INIT, TRG, FETC commands I think am making mistakes in writing these commands to the instrument. Any help is appreciated.

Thanks.

[Dennis_Knutson]

You are making a mistake with the very first command. You are doing a CONF:VOLT AC? or VOLT:CONF:DC? Anytime you put a ? at the end, that's a query (your are requesting data from the instrument). You then issue another write without doing a read so the query is terminated. As I mentioned, I don't have access to the manual right now so look up in the manual for the proper syntax of configuring a scan list. It may be as simple as removing the '?'.