Our problem is that when we configure the NI-6221 card for single-ended
channels, we lose data when reading more than 12 channels at a sample
rate of 5 KHz. We do not have this problem when reading all available
channels and the channels are set to differential. Though there are only
8 channels available when in this mode, and that may mean we are
not near the 12 limit. We sometimes have a reading failure when the
number of channels drops to 11 or 10.
We use:
1. a Real Time OS (RTOS) that is not supported by NI (InTime by Tenasys)
2. NI-6221 PCI data acquisition cards
3. Visual Studio 6 (can upgrade to VS 2003)
4. Intel PCs with MS-Windows operating as a process/thread under the RTOS
(the real-time program runs independently of any Windows application)
5. our own software for programming the NI-6221
We presently:
1. have a sparse document listing some of the registers and their functions
2. RTOS software that accesses the NI-6221 PCI card, reads digitized data,
and outputs signals.
We need:
1. documentation on programming the NI-6221 without the APIs or drivers
(including initialization, DMA transfers, etc.),
as they would be useless in the RTOS.
