save and load 1d array of digital wave form

[mohamedaboauf]

The application : Mechanical Copier

Component :

2 encoders.

USB interface 6501.

Step drive BDM 60.

Stepper motor.

Aim: 

we have an arm , 2 rotary encoders fixed on it. We can draw circle , shapes , other by this arm .

we want to save the motion of the drawing (signals of encoders) in file which made by labview and we load it to execute the motion again by step motor .

Problem :

we use labview 2009 to save signals by save HWS function using NI 6501(succeed ).

when we loaded file to execute it again , the motion of step motor is very fast than input motion so my drawing is corrupted .

[Efrain_G]

Dear mohamed,

I looked at your code and I saw that you are not using any timing VI. That means that you are basically running your code as fast as your operating system can. In this case your operating system might be faster than the actual rate at which you need to output. I would suggest you to use a DAQmx timing VI to control the sampling rate of your 6501. If you have questions on how to do that, feel free to look at the LabVIEW examples. Help>>Find Examples>>Hardware Input and Output>>DAQmx

[Dennis_Knutson]

Actually, adding a timing function will do no good since the 6501 is software timed. There is so much jitter and it's so slow in software timed acquisition that your recorded data is essentiall wortlhess, imho.

[Efrain_G]

Hi mohamed,

Dennis is absolutley right. Unfortunatley, the USB 6501 is one of our few boards that is software timed only. That means that the speed of your tasks will be determined by the speed of your operating system. With that said, if your generation is below 1 Khz, you can control the speed of your generation using software timing functions in LabVIEW.

[mohamedaboauf]

Thanks for replay

the generated wave is blew 1K Hz's

haw I can control the speed of your generation using software timing functions in LabVIEW?

When I use Count Read Dig Chan-Ext Clk example , error of stamp time

Property: SampTimingType
You Have Requested: Sample Clock
You Can Select: On Demand

[Dennis_Knutson]

No. You cannot use any hardware timing functions. Your DAQmx read has to set for single sample. Software timing means functions like the Wait (ms) or the timed loop.