Sync setting for HP 3458A Multimeter

[Almon]

Hi,

I am trying to calibrate a signal generator with a HP3458A by doing the following - set output - read value - generate offset - add offset - adjust sig gen - read value and so on. I then want to use the sig gen to characterise a transformer. I'm using a Modbus app to switch a relay over to allow the sig gen to stimulate the transformer after calibration. The problem is I keep getting an error as shown in the attachment and I can't get rid of it. Any ideas? I have attached my Labview code if anybody wants to comment on it - I'm new to Labview so forgive any stupidity in the code.Thanks.

[JÞB]

Almon,

OK I looked at your code.   if you want to call it that.  you need to look at the examples that ship with the 3458 driver!  

1) you are reading from memory but there are no measeurements in memory because you haven't triggered the meter to take a measurement.

2) you need to keep all calls to the meter on the same error chain (you will not be able to make the meter do anything else when it is taking readings)

3) read the hp programmers guide to gain some understanding of what the meter does 

[Henrik_Volkers]

use direkt sampling, trigger with sig gen sync

set sig gen

measure transformer input 

switch

measure transformer output (if ratio less than 20 use same range for highest performance)

do some math

all this lined up by dataflow, sorry can't read 8.6 ...

[Almon]

Hi Folks,

Thanks for all your suggestions - I have scrapped the original code (I inherited it from someone else - my excuse and I'm sticking to it!) and started again. I am now happy that I can talk to the instruments and read back measurements. I have a further problem in that I want to run my code in nested loops but can't seem to find a solution to this in LabView - am I looking at a TestStand solution for this type of code execution? I am trying to characterise a transformer for use in a new product. My sequence is:

1. Set a Sig Sen - read Sig Gen O/P with HP meter - feedback error to Sig Gen to adjust it to the proper set value - read Sig Gen again - repeat untill set value has been reached.     Drop out of loop.

2. Switch the Sig Gen and HP meter over to connect it to a UUT (a voltage transformer) using a relay and apply the Sig Gen output to the UUT - measure UUT value with HP meter - output the measured value to a spreadsheet

3. Set new (increased) value on the Sig Gen and repeat from step 1.

I have all the separate bits but I am having trouble with the loops and sequence. Any suggestions? Thanks.

Almon

[Dennis_Knutson]

I would suggest that you look at the state machine architecture. TestStand can certainly be used but you can easily do this in LabVIEW as well.