Pulse Generator for usb 6218 with exponentially increase

[Giakko]

Hello, I have a USB 6218. I have to check 2 stepper motors that take the signal on dev1/ctrl0 and dev1/ctrl1 for speed, A01 and A02 for the direction (forward and backward). I have to send a signal to 5 volt square wave to control the direction with a frequency chosen by  user  on A01 and A02. I must also send a sequence of pulses with fixed amplitude 5 volts and frequency choose by user. pulses must be sent with a frequency increasing exponentially from 0 to the frequency chosen by the user. how can I do? thanks for your help

[AndreaN]

Ciao Giakko,

you can take a look at this example to change on the fly the frequency of the generated pulse:

Generate a Continuous Digital Pulse Train With a Variable Frequency

http://decibel.ni.com/content/docs/DOC-3751

Regards,

Andrea 

[Giakko]

Ciao Andrea,

thanks for your reply. For example I would like to generate a train of pulses at 1000 Hz. when I start the VI , frequency of pulses start  from low values and then increase linearly or exponentially up to 1000 HZ. How could I do? thanks in advance for your help

Giacomo

[AndreaN]

Ciao Giacomo,

in order to change the frequency programmatically you can refer to the example in the previous post. You need do write on the property CO.Frequency.

If you want to change the frequency from 0 to 1000 Hz you could write some code that at a given condition gives the new value to the property node.

I'm attaching a simple VI to show you one way to do this, but there are several implementation depending on the condition you want to set.

In my example the loop rate is 100 ms and I set the new frequency every second (10 iterations). The Frequency values increment linearly from 0 with a step of 10.

Be aware of generating a pulse at 0 Hz, so read this KB:

Pulse Train Generation with Variable Frequency that Includes a Steady Zero Hertz

http://digital.ni.com/public.nsf/allkb/7656E39CD15D181786256E69006B8523?OpenDocument

Ciao,

Andrea 

[Giakko · Accepted solution]

thanks so much Andrea !! I solved
my problem !!