how to control pwm output which we r giving to ni9505 to control a motor?

[M.P.Singh]

sir

i made a system on that a dc motor is fixed to produce vibration. by using crio i wants to measure amplitude of vibration and its frequency and by this amplitude or frequency i wants to control speed of motor by pulse width modulation as if amplitude of vibration increases speed of motor should decrease for measuring amplitude of vibration i m using ni9234 and for output to motor i m using ni 9505   . i wants continous control of motor as amplitude value is changing. 

please tell me how we can do it or send me any example .

thanks

[Shreyas]

Hi,

Since you want to vary the motor speed with the vibration amplitude you measure you need the following toolkits :

1. Sound and vibration

2. Control design toolkit

You can use a PID control to vary the PWM in turn vary the speed of the motor. The following articles will help you through this:

http://zone.ni.com/devzone/cda/epd/p/id/5177

http://zone.ni.com/devzone/cda/tut/p/id/6143

When changing the period of the PWM on the NI 9505, any period is allowed EXCEPT for the following:

0 ns to 875 ns.  In this range, the FPGA will command the H-bridge to send out pulses, but some of the pulses will not be sent out of the H-bridge chip.

1175 ns to 1800 ns.  In this area, the behavior is undefined and sporadic (make sure not to run the motor in this area).

Kudos are welcome