how can we generate the PWM signal with NI motion controller card 7330

[CD wrioting]

dear all 

i am new to the labview programming . i have a the motion controller card NI 7330 controller. with this i want to generate the PWM signal and switch to this signal if a control signal becomes 1. how it can be done please any one suggest me for the detailed method as i am new to it and using it for the first time for the project

rgds

bnn 

[Jochen]

bnn,

before I can answer your question please provide some more information:

1. What's the purpose of the PWM signal? Is this supposed to be a control signal?
2. Is this a static PWM signal (fixed frequency and duty signal) or do you need to change the PWM characteristics dynamically?
3. What do you mean with "switch to this signal"? Do you mean you want to start the PWM generation when an external signal transitions to HIGH or are you talking about a real switching application with relays or solid state switches?
4. Anyapplication specific information will help me to optimize my suggestions.

Thanks and kind regards,

Jochen Klier

National Instruments

[CD wrioting]

thanks for your prompt reply.

for ur clear information here are the details.

1) i am working for the hologram writing so i want t ogenerate the PWM signal with variable duty cycle.

2) i need to change the PWM dynamically and in some case static too that means according to input decide whether to change the duty cycle or not

3)i have trhe switch IC for switing and the PWM signal generated by card will be send to that switch and in that switch there will be one another signal too so i need to switch betwwen the PWM and another signal according to the sensor input that i connect in the analog input in the card

4) the application is for writing the hologram data in the CD surface

hope with this information u are clear with ur confusion

thanks once again and hope to see some inforamtion and suggestion regarding it

[Jochen]

With this information I don't think, that the 7334 is the right board for your application. The 7334 is a motion control board for stepper motors. As control signals it provides a step signal with variable frequency and a direction signal (high or low for fwd. or rev. direction). The step signal is generated onboard and controls the motor's trajectory (acceleration, velocity, travel distance). The duty cycle of this signal can't be changed by the control program, so this signal can't be used for your application.

The PWM outputs provided by the 7334 is static. That means, you can set frequency and duty cycle only in software, which is quite slow and introduces significant and non-deterministic jitter (due to the asynchronous communication to the 7334 this is even true if you are using a real-time operating system). These limitations don't seem to meet your requirements.

I still don't have a good idea about your timing requirements. If your response times requirments are in the upper milisecond regions (10 ms and above), you might be able to use the 7334. If low jitter and fast response times are important to your application, there are several alternative solutions including LabVIEW Real-Time with a multifunction data acquisition board and LabVIEW FPGA with an R-Series board.

Regards,

Jochen