AT-MIO-64E and digital output

[Thijs]

Hello,

I've just come to the conclusion that my AT-MIO-64E doesn't support the
function of a buffer for digital output.
Does anyone know if there is a secure (ms level) way to build a vi that
reads an array of U8 (150,000 points array) with digital data (1000Hz) so
the output array take 150 seconds and then send it to my digital outputs,
i've tried the "wait" command in labview, but it isn't that secure!

Best regards,
Thijs Boerée

[Conseils]

I notice in the HELP for Labview 6.1 that there is an example "buffered handshake output.vi"

I suspect that this might do the job with some jigging of the configuration

'DESCRIPTION:
This example VI can only be used with boards that support handshaking such as the 8255 based DIO devices, Lab and 1200 devices, AT-MIO-16DE-10, DIO-32HS/653x devices, and AT-DIO-32F. This VI transfers data from your digital DAQ board to an external device using a two-way handshaking protocol.
'

[Shea C]

Hello Thijs,

Thank you for your inquiry regarding digital output timing. It sounds like want to use software to write the digital points out at a rate of 1000Hz. When you mention that the wait command is not �secure� I assume that you mean it creates an output rate that is not accurate. The wait function can be interrupted by software and therefore the rate at which you are writing data out may not be accurate. Even though there is no way to guarantee a rate of 1000Hz using software there is a better function that you could use to make your output rate more accurate. The Wait Until Next ms Multiple function waits until the value of the millisecond timer becomes a multiple of the user specified millisecond multiple. This can be found in the Functions>>All Functions>
>Time and Dialog palette. Use this function in a For Loop to write points until the array of 150000 points is empty.

I hope these resources help. Let me know if I can further assist you.

Shea C.
Applications Engineering

[Ben]

Hi Thijs,

It's me again. I was hesitating to reply to this Q because I am busy and answers of this type usually get a one start rating but,
TO h#$l with answer ratings!

You can not do what you are asking with that board with any degree of determinism.

Now if you wanted to do 10Hz and there was nothing else happening on the machine, thne the answer would be maybe.

If you wanted to do 100Hz and you could tolerate jitter on the order of 100 to 1000 ms, then the asnwer is maybe.

But, to do 1000 Hz deterministicly over 150 seconds, NO WAY! This will only end up being an exercise in frustration.

You need hardware timing to get determinism on a non-RT OS.

So,
Get another board that supports bufferd DO,
or
Mover to LV-RT
or
Live with indetermi
nism.

Bracing for a one star rating,

Ben

[LucaP.]

4 Stars!

Luca

[Ben]

Thank you Luca.

Some times its hard to say no.

Ben

[Thijs]

Hi everyone,

I allready resolved the problem,

Now I use 2 Dac outputs of my AT-MIO-64E en i can buffer them! I just values
of 0V or 5V it works great! So i don't need another daq card!

Thanks anyway,
Best regards,
Thijs Boerée

"Ben" schreef in bericht
news:50650000000500000001630100-1077587809000@exchange.ni.com...
> Thank you Luca.
>
> Some times its hard to say no.
>
> Ben

[Ben]

Excellent approach!

I have used that method as well.

But for the sake of future readers, we should observe that this work-around is required because that board can not do what you wanted.

Keep thinking "outside the box" and have fun!

Ben