05-17-2010 10:37 AM
I am currently working on a Agilent 34970A and finally manage to meassure with it in Labview.
But I am having some problems converting a measurement string to a array. Seems like is it only the first string which is converted.
I placed some "probes" on the problem places.
05-17-2010 11:43 AM
Look for the VI named "hp34970A list to array" in the instrument driver library package.
It takes the comma separated string from the Agilent unit and converts it to a numeric array
05-17-2010 01:06 PM
05-17-2010 02:03 PM
The format specifier should at least begin with '%.;', (the user is on a comma decimal system and the device return point based strings.
Perhaps you should use '%.;%e'
Ton
05-17-2010 02:08 PM
05-17-2010 05:01 PM
I have been using the 34970A for years...
Here is my "scan now" vi, that I modified from the Agilent example vi's.
This one outputs both a numeric and string array just use the one you need.
I find I use the strign array ouput to save to files and the numeric output for inscreen indicators.
05-18-2010 04:03 AM
Thanks for all the fast answers to my question.
All of them solve my problem
It seems like your labview code does not program the Agilent unit.
Are you only getting the readings out in labview ?
I am used the advance scan example but the Agilent "buzz's" thouge the channels , instead of the normal "click click click" sound.
Do you/all of you have an idea of what that it ?
The measurements I am working on is a test rig, for testing of a Co2 refrigeration plant on my university
05-18-2010 09:19 AM - edited 05-18-2010 09:24 AM
You will find that for best results you should access the 34970A in two steps.
1) configure all the channels for the measurment type, range, scaing, etc.
---I have a set of vi's to configure channels for the most common functions I use (AC or DC Volts, Temperature, set scaling, etc)
2) Trigger a "scan" and receive the data.
---Thats what the vi I posted does.
In the Vi package from NI there are "EZ"-vi's that set the channel function then do a scan but I have found this to be rather ineffecient. Specially when you need to take lots of measurments in a short time.
The scan speed is determined by several factors like auto ranging is slower conpared to setting the range, 6 digits accuracy is very slow 4 digits is very fast, the number of power line cycles (PLC) used for integration...
I jsut had the same conversation with a coworker recently and here is something I found on the Agilent site
How can the 34970A measurement speed be maximized? |