sample rate, scan rate

sample rate = how many samples per channel per second
scan rate = how many scans per second

Example:

4 channels ( ch 0,1,2,3 )
take sample rate = 250 samples / channel / second, it means 1000 samples / second
take scan rate = 250 scans / second, it means 1 scan = 4 mlliseconds

Illustration for interval scanning:

Scan | Channel | Time (microseconds)
-------------------------------------
0 0 0
0 1 1
0 2 2
0 3 3
-------------------------------------
1 0 4000 (4 milliseconds)
1 1 4001
1 2 4002
1 3 4003
-------------------------------------
2 0 8000 (8 milliseconds)
2 1 8001
2 2 8002
2 3 8003
-------------------------------------