mazen_abs

convert am to fm

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Dears ,

how can I convert the analog output from inverter AM  type to pulses as FM type

Thanks in advance

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Are you talking about radios? Or what? Please explain.

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If i'm reading this correctly you could try a google search for 4-20mA to PWM converter (Pulse width modulation),

Or 0-10Volt to PWM converter.

 

Steve

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I am talking about Mitsuishi VFD

or

is there a special forum for Mitsubishi VFD ?

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Please explain in more detail what you want to accomplish. Are you using an output from the VFD to send a signal to something? Or are you trying to control the VFD via an input signal? Or are you talking about the main output from the VFD?

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AM and FM is not terminology you will see with VFD or servos.

AM would not be practical because of huge losses. output is switched in order to ensure high efficiency. carrier frequency is usually 4 or 8kHz. this is switching speed. output frequency is 0-60 or so Hz but... this is not the smooth sinewave people usually image, it is a PWM version of sinewave (PWM - pulse width modulation).

https://en.wikipedia.org/wiki/Pulse-width_modulation

 

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I agree with @panic mode, but it may be that the topic starter is referring to the "AM"/"FM" terminals (0-10V Analog output / Indicator output), and not "AM"/"FM" (Amplitude/Frequency Modulation) as we are thinking right now... Maybe the topic starter is referring to the terminals on the VFD. But this is impossible to say without the topic starter giving more information and that is why I asked for it.

So again, please explain in more detail.

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thank you for your answers , but would you please explain more about the difference between this tow types (AM / FM ) 

is the difference in output signal  , or in the way that convert DC to AC ?

and if you have reference explain this in more detail , I will be grateful to you 

Thanks in advance

 

 

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Terminal FM = (pulse train output)
Terminal AM = (analog voltage output 0 to ±10 VDC)

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Which inverter do you have (type/model/spec)?

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The 'AM' signal out from the VFD is an analogue signal which is selectable between voltage out at 0-10 volt or current out at 4-20mA.

The 'FM' signal out is primarily for use with a frequency meter for remote speed indication this output gives a linear 24 pulses a second, the default setting is 1440pps at 60Hz it has a very low current out capability of around 1mA (I think) so this has to be taken into account if driving something else.

 

Steve

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