Data is unnormal with hw timed acquisition with dma on aiex3,please help me

[ganxiaobo]

Hello,I want a continuous mode,I modify from example aiex3:

1) enable continuous

const tBoolean continuous=kFalse ;---------->const tBoolean continuous=kTrue;

2)config dma to ring mode

   status=dma->config(0,tDMAChannel::kNormal,tDMAChannel::kIn,dmaSizeInBytes,tDMAChannel::16bit);

   -------->status=dma->config(0,tDMAChannel::kring,tDMAChannel::kIn,dmaSizeInBytes,tDMAChannel::16bit);

3)get data in a infinite loop

   while(bytesRead<totalNumerOfBytes && (kNoError==status))---------->while(kNoError==status)

I run my program without connecting to any signal source,the data I get is always -0.009239. With the program runing,I connect to a signal source , the data I got is

still the same -0.009239. the output of aiex2 is normal .My board is pxi6259 and OS is QNX.

[JoeFriedchicken]

Does aiex3 report good data without any changes? Have you used DMA with QNX before?

[ganxiaobo]

Thanks Joe Friedchicken.

No error is reported while running aiex3,but data is always -0.009239.

[JoeFriedchicken]

Do you know if the device has been damaged? If you have access to a Windows PC, please use the MAX test panels to confirm that the 6259 can acquire data correctly.