error -50 ... using two counters at the same time

[jolly jumper]

hello there,

I'm trying to run two counters at the same time with different frequencies and number of samples and get the following error:

Error - 50103

(counter number 1 works but the error just affects counter number 0)

My device: PCI-6024E

Please take a look at the picture for details!

Thank you,

kind regards Peter

[Andre_Saller]

If you configure a counter to create a finite pulse frequency, a second counter is needed to perform this task. The second counter gates the first one. So if you configure counter 1 to generate a finite pulse frequency, counter 0 will be reserved, and can not be used for anything else, as long the generate finite pulse task is running.

[jolly jumper]

Hello Andre,

thanks for your reply. I suggested that your explanation could be the reason :/. Can you give me an advise how to avoid this? It's necessary for my application that I can create two pulse trains simultaneously (I'm working on a plotter). The first motor needs a frequency between 1 and 100 kHz and the second between 100 and 1800 Hz.

Is it possible to change the configuration to "continuous pulses" and check the number of generated pulses in a loop or something like this?


please help me again,

kind regards peter
 

[Andre_Saller]

If you would change to "continous pulses" you wouldn´t need a second counter per task, thats right. To count the generated pulses you would need a counter. So this does not improve your situation, still you would need two counter per motor. Best would be to use a counter-card (660x).

Maybe you could use an analog input, to count your generated pulses, but this will create a lot of overhead (you have to acquire your signal at a high rate and analyze de acquired signal to detect the number of pulses).

So from my point of view I don´t see a solution with your current hardware. You will need four counter for this application, so you either have to add a second multifunction board or use a counter-card.

Hope this helps!

André

[jolly jumper]

Hello Andre,

yeah I unerstand the problem, but I think it's weird to say that my NiCard has two counters, although I can't use the second counter simultaneously :).

Counting the edges brings to much overhead, like you said. That's why I'll use one counter for the high frequencies 1 - 100 kHz and generate the second pulse with a timed loop and a boolean that changes its state (smallest timebase 1 ms -> max. 500 Hz) and I can also add a delay of one millisecond so I'll get 250 Hz.


For the range from 1 till 100 kHz, should I take the 100 kHz timebase or the 20MHz timebase?

thanks for your help,

kind regards peter

[Andre_Saller]

Use the 20 MHz Timebase, with the 100 kHz Timebase you don´t have enough Resolution to generate a good 98 kHz Signal for example, as the counter has to dived down your output-signal based on the Timebase somehow, so using the 100 kHz Timebase, the next possible lower frequency to generate would be 50kHz.

Message Edited by Andre_Saller on 09-12-2006 04:25 AM

[jolly jumper]

I suppose that there can occure problems with the 20 MHz timebase when I try to generate e.g. 2000 Hz   (Error..... either choose a different timebase or a different number of pulses to be generated ....). I had this problems before that's why I changed the timebase to 100 Khz.

But I will try it !!
kind regards peter

[jolly jumper]

hello andre,

I had an idea and want to ask you if it would make sense to take the 100 kHz timebase (1-10 kHz) for lower singals and the 20 MHz timebase for higher frequencies and set this option before I start the vi? (from C .. I'm using a dll)..

kind regards peter

[Andre_Saller]

I guess you have to use such a solution. With the 100kHz you don´t have enough resolution for the high frequencies, with a 20 Mhz you might get a overfolw for the very low frequencies, so what you suggests seems to be a good solution: Let the user select a range first, accoring to the range you can use the 100kHz for the lower range and the 20 MHz for the upper range.

[jolly jumper]

Now it works! I thank you very much for your advise Andre! 😉

best wishes peter