DAQ Counter

[bizeul]

I have a AT-MIO-16-XE50 multiDAQ card.

I send a external TTL signal on the source channel of the counter. Either with MAx or Labview vi, the counter counts 2 or 3 or 4 randomly despite there is just one rising edge of the TTL signal (I visualize this signal with a oscilloscope and it is clean)

What is my error ?

[Marc L.]

Hello,

Are you sure of your TTL signal ?
For example if the rise/fall time is greater than 50 ns, than the counter will give erroneous count values.
You will find other details here :
http://digital.ni.com/public.nsf/websearch/E84361EAAF6C092686256AAA007ADA7B?OpenDocument

regards,

Marc L.