PCI-1202/1602/180x Series Card
Multi-Function Boards
User Manual/ Ver. 4.8/ Mar. 2015/ PMH-0014-48/ Page: 97
The A/D conversion data in FIFO are in the same sampling rate (refer to (1), (2), (3)).
For example,
the scan channel is 1
2
3
the pacer sampling rate is 330 k
We want a 110 k sampling rate for channel 1
We want a 55 k sampling rate for channel 2
We want a 11 k sampling rate for channel 3
The hardware will scan the analog data into FIFO as follows:
1,2,3,1,2,3,1,2,3,1,2,3,1,2,3,1,2,3……
total 330 k
every 1,1,1,1,1 is 110 k
every 2,2,2,2,2 is 110 k
every 3,3,3,3,3 is 110 k
The software has to fetch the 2,2,2,2,2 in 55 k, therefore the software averages the continue two 2
into one 2 to get 55 k as follows:
2,2, 2,2 2,2, 2,2
2, 2, 2, 2,
55 k
The software has to fetch the 3,3,3,3,3 in 11 k, therefore the software average the continue ten 3
into one 3 to get 11 k.
There are very heavy computation loads for the PC to execute the MagicScan function. These
computation loads are given as follows:
1.
Averages the continue N data into one data to get different sampling rate data
2.
Compares each A/D data with the HI/LO alarm limit
3.
Saves the A/D data into memory if the save flag is enabled
The MagicScan function described in this section can be realized in Pentium-120 and Windows 95
without other running programs (like anti-virus of firewall).
Refer to
Sec. 7.8.6
for driver source.
Refer to
Chapter 11
for demo program.
Refer to
Chapter 12
for performance evaluation