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ibdev return value issue

ibdev return value issue

Dear all, sorry for bothering...

I have some question about ibdev return value.

According to the document, it says: If successful, returns a (non-negative) device descriptor. On failure, -1 is returned.


I follow the sample code to check if the instruments such as agilent 34401A connect with GPIB connector is succeed, when I remove the agilent 34401A from GPIB connector and use ibdev command to verify if it's removed succeed, the return value isn't return -1, it is display 31256 (see attachment).


I can't understand why..I need some help, how to check the instrument is removed from the GPIB connector?

Any suggestion I am very appreciate...

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Re: ibdev return value issue

I'm having the same problem. In this case I have 2 instruments communicating through GPIB and the ibdev comand (even when the cable is not connected) returns 31256 and 31257. I have no idea how to solve this problem, help me please.

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Re: ibdev return value issue

You have to confirm that the connection was successfully establisthed in MAX first, then you'll go for the programming.

It seems the connection failed in MAX, and the scan for instruments didn't work. You have to solve this issue first.




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Re: ibdev return value issue

Hi Kuolun ,


If your device(Agilent 34401A) connect successfully , you should see the correct instrument identification as below :








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