advanced scan vi agilent used for continous measurement

[siva0182]

Thanks.The modified Vi with the trigger into the while loop works but only in highlight execution mode.

When I run the same in normal run mode ..the channel becomes configured to  Voltage measurment  in DC and displays some -ve no and unit is also not deg C.

but in highlight execution mode the readings and unit are correct.

[siva0182]

What could be the problem if the vi works properly in highlight execution mode but does not work well in a normal run mode?

[RavensFan]

That is usually a sign of a race condition.  Improper use of local variables where you can't control the timing of when they are being read or written to.  Your VI doesn't look like it would have that problem, but I don't have the Agilent subVI's to look into.  Sometimes those driver VI's are rather old and the original writers of them didn't use the best LabVIEW practices in writing them.  They would use local variables and stacked sequences unnecessarily.

The other possibility is that you need to have more waits, or longer waits between different commands to the instrument.  Execution Highlighting might be slowing down the code enough to create a long enough wait time between commands for the instrument to be able to handle.

[siva0182]

I am trying to read at the maximum possible rate and cannot afford to provide more delay times..But has some one used this set of Vi's in labview 8 and if it had worked please let me know which set of driver set vi you are using.

[RTSLVU]

I really do not know what to say as I have been using these iv's for quite sometime now and have not ran into any of the problems you have described in this thread.

I have never had to insert any time delays what so ever...

Maybe if we could see all of your code we could spot something else that is causeing your problems.

[siva0182]

its the same vi that i posted earlier but with the corrections as suggested in this thread.

Anyways I am posting the latest vi here 

[pri2686]

Hi everyone,

I have to acquire DCcurrent values from agilent 34970A using the third module and channel 21(321). I have looked over the examples and your posts and created, some sort of similar vi. But when I run the program, its scanning for a microsecond and it stops. I included while loop too. But the problem remains the same.

Can any one help me regarding this,please.

Also i need to include the time in the readings. I mentioned that in the scan list. So how will the readings look like? (dc current value, time) is this the format? i need to have the time included in this because i have to generate a signal out of this.how will the readings differ if they are in DBL format?? I am not able to understand this. My doubts may look stupid, sorry for that, but i need to knw this.

I am attaching my vi. Please let me know abt the possible changes or corrections in this.

Thanks 

[pri2686]

Hi again,

I forgot to mention that in my scan list i included only time(The agilent user guide says that the default type is relative) but not units. And I used the same 'while loop' which siva0812 has used. Is it right to use the same loop for mine too? I am new to labview and I have a very short period to finish my task. Can you please answer my queries?

[Dennis_Knutson]

Are you changing any of the front panel controls from what you posted? You have no channels defined and the value of the boolean you have wired to the while loop's termination terminal is wrong - the loop will only run once. Just delete that control and right click on the termination terminal and select 'Create Control'. You will then have a front panel control with the correct mechanical action.

You don't need both Conf EZ and Conf Scan.

[pri2686]

Yes, I am changing the front panel controls. I am using COM1 as the visa resource in. I defined only a single channel(321) in configure ez.

I deleted the control in while loop and did exactly what you said. And i did find a control saying 'stop'.and now i find that the loop is running. Thank you.

And what should I do if the instrument gives an error saying that 'DMM relay count data lost'?