increase the freq of square pulses generated by the counter

[lalitha]

I have program that outputs a finite train square pulses through a counter to run my step motor. I find that this program can genrate a sq pulse at a freq of 1080 Hz max. Is this a limitation of my program ( I have attached a copy of my program) or of my interface card (PCTIO-10, one of the older cards from NI) ? I use labview 5.0 on a windows NT , pentium MMX machine.

Is there anything that I could do in my program to generate pulses at a higher rate ? I havent specified any of the low level parameters for the pulse config.vi in the program - could setting these values help in generating higher frequencies?

thanks very much,
Lalitha.

[Filipe A.]

Lalitha;

You are doing a Software timed operation, that is why you can't go faster that 1KHz, which is roughtly the Windows limitation for tasks handling.

The best way to do that is by setting up a hardware timed operation. You can see examples on that at Search Exmaples->Data Acquisition->Counters->Finite Pulse Train.

Hope this helps.
Filipe A.
Applications Engineer
National Instruments

[lalitha]

it certainly did - I am using the finite pulse generation - intermediate vi for this operation now,

thanks
Lalitha.

[Tiano]

Good Day Lalitha!

My name is Tiano�I have been busy trying to run my stepper motor using LabView. At the moment I have trouble to get together a vi that generates a pulse train with variable frequency, just like the one you requested. From your comments I have the impression that you are way more advanced in that matter than I am. Can you please provide me with a copy of your vi so that I can guide myself in achieving my aim?

My e-mail is cristiano_cerca@yahoo.com.br; please reply and who knows�maybe we can maintain a contact.

Thanks in advance

Tiano

[lalitha]

hi Tiano,

you should be using the vi in the Search Exmaples->Data Acquisition->Counters->Finite Pulse Train.

this is how you modify this vi to generate pulses at varying frequency.

Set Device=1, Counter=1, Number of Pulses=100, Frequency Array=10, 100, 1000, 10000.

[Place an array container on the front panel. Drop the Frequency control into the array. On the block diagram place a
For loop around the whole program. Move the new array to the outside of the For loop. Wire the array to the edge of the for loop and then to the terminal that the Frequency control was wired to before. One
the front panel, set the first four elements of the array to the values 10, 100, 1000, 10000.]



I am attaching a copy of this mod
ified vi for your ref.

hope this helps,

Lalitha.