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Why did I measure incorrect PWM signal from my [c]FP-PWM-520's Vout?

Hardware: Compact FieldPoint>>Discrete I/O Modules>>cFP-PWM-520, FieldPoint>>Discrete I/O Modules>>FP-PWM-520

Problem:

I write 0.5 to the channels of my [c]FP-PWM-520 in Measurement & Automation Explorer (MAX) and the return status of the write operation is "Success". However when I measure the output with an oscilloscope I see a large DC component added to my output signal. Why is this?



Solution:

This is expected behavior. Without a load, you will measure a DC voltage added onto the PWM signal. The solution is to add a 1 KΩ resistor between the Vout and COM terminals.



Related Links: FP-PWM-520 and cFP-PWM-520 Operating Instructions

Attachments:





Report Date: 01/15/2007
Last Updated: 01/16/2007
Document ID: 45E4LQBF

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