Erro open agilent 34970a

[Teef]

Hello, I'm very new on Labview, I'm using an agilent 34970A. (I'm french, sorry for my english).
I've made a small program with agilent drivers to get temperatures and it does work. 

I would like now measure a voltage. I can read it directly on the front panel of the agilent, BUT when i try to read it with the labview programm with the function monitor, the front panel indicate that the channel is open, which is not because I could read it one minute before with the front panel.

I don't understand the problem because my program is very simple and excutable, there is no communication trouble between the computer and the agilent, so i'm really asking with does the agilent indicate that the channel is open ?...

I'm sorry for bad explications, I hope your understand my trouble, I've give you some picture to illustrate my purposes.

Thanks a lot  in advance 

[ben64]

1- Your VISA ressource name shows you are using a GPIB interface but then you set values for serial communication. Which are you using, GPIB or Serial?

2- You didn't connect an indicator to the monitorChannel Output so even if the Monitor vi works correctly you will not see any value on your front panel.

3- Your FOR loop doesn't have any wait time inside so it will try to run as fast as possible which is probably not necessary.

Ben64

[Dennis_Knutson]

The front panel of the instrument also indicates an error. You need to query the instrument to see what the error is.

[Teef]

Hello Ben64 and thanks you very much for your very quick response.

1- i'm using a GPIB interface, so I removed the set values for serial communication.

2- I connected an indicator, (I was trying to make the program as lighter as possible to understand what cause the error 'open channel')

3 - I put a wait (10 000 ms) but the problem  is persistant, while with an other similar programm (in attachment I don't have the trouble).

Tanks you in advance

[Teef]

Hello Dennis_Knutson, 

I don't think the problem comes from the instrument because :

I can read the voltage from the front panel whenis not connected to the computer and it does work for temperatures measurements.

[crossrulz]

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@Teef wrote:

Hello Dennis_Knutson, 

I don't think the problem comes from the instrument because :

I can read the voltage from the front panel whenis not connected to the computer and it does work for temperatures measurements.

---

Dennis isn't saying there is something wrong with the instrument.  But if there was a communication error, the instrument would show that error.

[Teef]

Ok, but why, because when I use another program for measure temperature (in attachment) I don't have any communication problem between the instrument and the computer.

Ok for the forum rules of politeness, I will never say 'thank you' again 🙂

[Teef]

How can I know if it's a communication error ?

[Dennis_Knutson]

You run the VI on the palette for checking an instrument error. This generates the ERR? query. It will return the instrument specific error code that you would look up in the manual.

[Dennis_Knutson]

And look at the block diagram of the Monitor function to see if the relay is actually being closed. What you see before running the VI is irrelevant since you are doing a reset before the loop.