Can't get readings from 3458 meter to refresh

[Jim_Glanz]

I am trying to configure an Agilent 3458 meter to take a single measurement, but I seem to keep getting the same reading back. It is like I am not clearing the buffer of the previous reading and keep reading out the first measurement taken. I can get the meter to change the reading if I reinitialize the meter before each reading.

Do I need to initialize the meter for each reading? Does not seem right because I the open and close the VISA session for each reading.

My setup is using a switch matrix Agilent 34972 with a mux card (I am not using internal meter of 34972A because of accuracy needed). I would like to take a reading for each mux channel, but again the first reading is the same as the last.

Attached is the example code from the 3458 NI driver that I modified with a for loop to take 5 consecutive readings. I am probably overlooking something simple but I need some help

Thanks

Jim

[Dennis_Knutson]

Do NOT post VIs in a beta version of LabVIEW! There is a special beta forum for that.

[Jim_Glanz]

Sorry,

Forgot I was using 2012, here is the VI in 2011

Jim

[Todd_Lesher]

One way is to look inside the driver VIs and see what SCPI commands are being used.

I almost always use the provided drivers only as starting points.

[Mark_Ramsdale]

Hi,

Not being familiar with these drivers I would ask if you need to configure the multipoint for each loop.  Can this be done outside the loop.

Also, is there a "start measurement" that might go between the configure and read.  Is the 'same' measurement you see a value pegged due to the range?

Does the measurement change between runnings of the VI?

Does this seemingly straightforward data collection match any of the sample VI's in the driver?

[Jim_Glanz]

I only want to measure one single point between measurments then switch the mux channel on the 34972 and take another reading for about 10 channels.

3548 drivers

I attached a link to the drivers I am using, they are the project style.

Thanks

Jim

[Dennis_Knutson]

I don't understand. You are not switching anything in the code you attached. You are taking multiple readings of the same point.

[Mark_Ramsdale]

You might try changing the read VI polymorphic to multiple points, even thought multiple is only 1.  This is per the example for single point Vs example of multi point.

I looked at the driver, I think you could loop single point measurements, but multipoint of one should work.  If you are planning on trying to put the mux "between runs" of the looping of the DMM reads  I don't think it would matter if you use multipoint or single point VI's. 

[Jim_Glanz]

Dennis,

I stripped the code out and just made a simple loop to keep it simple.

There is a mux in the for loop of the actual application.

What I posted is just a modified example of the single point measurment vi. from the example folder of the 3458 driver

Jim

[Jim_Glanz]

Still having problems with this. I am using NI approved drivers and should not be having these problems. It shuold be setup and go!  I have tried other 3458A meters to eliminate the meter. One thing to mention is that I have a ENET/GPIB 1000 for the GPIB interface. I would think that this should not matter. Any ideas? termination characters maybe? I am good for one read unless i reset the meter. I am triggering properly and can see the measured values changing on the front panel of the meter, but when reading fromn the memory I only get the same value back from the first meter trigger.