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General => Technical support => Topic started by: cch1955 on December 10, 2015, 10:58:30 AM

Title: PWM output frequency stability
Post by: cch1955 on December 10, 2015, 10:58:30 AM

I am using Fx2424 to drive a servo amplifier.  The frequency generated by the Fx2424 will be in the range of 200Hz to 10KHz. The accuracy from the manual looks good for my application.

I would like to know how stable the output frequency is once set. My concern is no so much the accuracy but once the frequency is set, how much does it drift around ?

Title: Re:PWM output frequency stability
Post by: support on December 10, 2015, 04:48:59 PM

It should be as stable as the crystal frequency since the PWM frequency is controlled by the on chip timer hardware and not affected by PLC execution time.

Title: Re:PWM output frequency stability
Post by: cch1955 on December 11, 2015, 07:54:34 AM

I appreciate the quick response. Its good to know this function runs outside of the PLC and is crystal referenced.  I did some testing with my scope and within the range I need it looks very stable and clean.

Thanks