Try to start 2->error: Counter No DMA channel aviable (PCI 6601)

[Overman]

If i try to start to counters ( Encoder measurement), the first Counter start correct, but if i try to start the second counter i get a error "no DMA channel aviable".

I use Visual Studio 6. Do have somebody a sample programm to show me the correct handling with this DMA channels?

Thanks for helping

[RobertoBozzolo]

This error usually arises when you are trying to use more DMA channels than available on your computer: are you performing other tasks on the acquisition card (i.e. analog input / output) while you are acquiring the counters?
The general solution to it is to transfer some of the acquisition/generation tasks to interrupts in order to leave DMA channels free for other tasks. Use this instruction to do this:
Set_DAQ_Device_Info (1, ND_DATA_XFER_MODE_GPCTR0, ND_INTERRUPTS);
customizing it to your needs.
Since DMA is faster and more adapt to high data volume transfer, usually I set acquisition and generation to use DMA and set counters to interrupts, but your application can require a different setup.

Hope this helps
Roberto