PCI-4451 Digital I/O

[lukeB]

Hello, I wanted to use a PCI-4451 to acquire digital data (outputs of a CAN) at high data rate (let's say >1Mb/s) but I haven't been able to find the maximum data rate of this I/O. So I've made some tests using VIs from DAQ-Tradional driver and it seems that input data rate is highly limited.
My test setup was a square wave generator connected to a digital I/O set as an input.
The labview VI was just reading continously the input datas on the digital line and displaying the data on a graph or saving 1 and 0 in a file text.
It appeared that for frequencies above 50Hz, the acquired signal was distorded (spikes, duty-cycle and perdiod fluctuations) while the input signal was perfect.
Could you tell me about the maximum data rate possible to acquires digital signals on digital I/O port of this board?
I think that the problem is not hardware but software, I was ok with NiDaqmx (I worked on a NI-DAQ6016) but I think that it does not support this board. So I think that the problem is about my use of DAQ-Tradional VIs (I use DIO config and LineRead in a while loop).
If you have any example of that kind of aplication it would be helpfull.
Thanks a lot

[lukeB]

need help please!!!

[Mathieu_R.]

Hello Luke,

First, if you need CAN in your application, perhaps could you consider using NI CAN hardware, specifically designed for CAN.

Second, if you suspect your code to be erroneous, post on the forum a small part of it, wich isolate the problem.

About your code, use only once 'DIO config', then to loop on the 'LineRead', and place a timer in the loop.

Cordially,


Message Edité par Mathieu R. le 01-07-2008 11:01 AM