the problem about DIO-32HS in pattern I/O mode when useing external REQ!!

[alvin]

Hello:
i'd try to use both the internal REQ and external REQ mode to read 16 bit pattern by DIO-32HS with pattern I/O , and the program run well by useing internal REQ mode ,even in high freq sample rate.but in external REQ mode....when i sampled about 100K times
with 2MHz external sampling rate, then the Error Handler shows "Overflow error"....i wonder why there are no "Overflow error" in internal REQ mode when using higher sampling rate then 2MHz?? and what can i
do in using external REQ??because i have to use external REQ with 2MHz sampling rate and sample more then 10M times in pattern i/o mode.....

best regards

[bman]

Alvin

The transfer speed of the PCI bus, which generates these errors, is independant of the clock you are using. Check you external clock signal. There may be noise on it that is generating extra pulses which is making the frequency greater than you think. If you have a DAQ board with a counter on it, check the freq. of your signal to verify.

Brian