Error When Opening a Device (TG124A).

I wrote a short program(In c#) that uses the tg_api.dll to control the signal generator. I used the simple example provided by the SDK as a reference, but when invoking

tgOpenDevice(device)

I get a ‘-3’ error, which corresponds to tgDeviceInvalidErr

I am using ‘0’ as the device value. Is this correct? All the drivers are installed and i can run the signal generator from the Spike GUI.

Is there any more information about what can cause the error?

[Andrew]

Hello Nazar,

I’m looking at this function right now and there is only one location where this error value (-3) can be returned. The code for this is below.

if(device < 0 || device >= TG_MAX_DEVICES) {
return tgDeviceInvalidErr;
}

where TG_MAX_DEVICES = 4.

So if the device integer provided is less than 0 or greater then 3 then this error (-3) is returned. I would look into the interop between your C# application and this function. This integer argument is not being passed properly. You are using DllImport and setting the calling convention to Cdecl?

Regards,
Andrew

• This reply was modified 6 years, 9 months ago by Andrew.

Hello Andrew

With your information, i was able to fix the problem. I used the bb_api as a guide, so assumed the device id had to be a reference, which was the problem.

Bad:

[DllImport(“tg_api.dll”, CallingConvention = CallingConvention.Cdecl)]
public static extern tgStatus tgOpenDevice(ref int device);

Good:

[DllImport(“tg_api.dll”, CallingConvention = CallingConvention.Cdecl)]
public static extern tgStatus tgOpenDevice(int device);

Thank you very much
Nazar

[Author]

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