Raw data is in the native format and organization of the device, read directly from the device or buffer without scaling or reordering. The native format of a device can be an 8-, 16-, or 32-bit integer, signed or unsigned.
If you use a different integer size than the native format of the device, one integer can contain multiple samples or one sample can stretch across multiple integers. For example, if you use 32-bit integers, but the device uses 8-bit samples, one integer contains up to four samples. If you use 8-bit integers, but the device uses 16-bit samples, a sample might require two integers. This behavior varies from device to device. Refer to your device documentation for more information.
NI-DAQmx does not separate raw data into channels. It returns data in an interleaved or non-interleaved 1D array, depending on the raw ordering of the device. Refer to your device documentation for more information.