How do I read the channel numbers using a 34970A DAQ with the 34908A MUX in Labview

[jefska]

I've downloaded the driver for the HP34970A for LV 8.0 but do not see any VI that has an output that indicates what channels are being scanned when inputting a channel list.  I’m taking temperature measurements using the EZ Temperature VI.  For example, my channel list is "101:110, 115, 116".  When I perform a scan on the channels I would like to know for sure these are the channels that got scanned.  How do I output all of the channels that were scanned and is there VI that does this and I'm just not seeing it in the HP34970A palette?

Any help would be much appreciated.

Thanks.

[Mark_E]

Hi jefska,

There’s a tradeoff with using the EZ functions: they’re easy to start using, but lack advanced features. It appears that in the Advanced Scan Example, Readings is an array. It should contain the information for the channels as well as the readings.

Another option is that in the EZ Temperature VI (as well as others) there is an HP34970A List to Array VI that appears to only be outputting the double numeric, but it also has a string output with no display. That should give you the scan list.

Hopefully that gets you started in the right direction.

[Dennis_Knutson]

If I remember correctly, the only reasons the actual scan list would not match what you specify is if you address a card that is not present or if the channel is no present on the card (i.e. channel 20 on the 16 channel card). If you do something like this, then I think the instrument will generate an error. There is the error query function you can run.

[jefska]

Thanks for the replies.

I was able to solve the issue by using the SCPI command ROUT:SCAN? which does a query on the scan list.  This helped me determine what channels were currently in the scan list so I could echo them to my UI.

jefska