MD30C Frequency control

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MD30C Frequency control

Postby liteace » Sun Jan 07, 2018 8:54 pm

I need a bit of help with the frequency control output, I see in the user's manual it says:



"Speed control PWM frequency up to 20KHz (Actual output frequency is same as input frequency when external PWM is selected)"

I will be using external 5k potentiometer to control the PWM but how do I change the frequency what would need connecting for this ?

Thanks
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Re: MD30C Frequency control

Postby ober » Mon Jan 08, 2018 5:28 am

Please use 10K instead of 5K, we notice potentiometer lower than 10K will generate unstable frequency and generate a lot of heat.
As for frequency control, if you are using on board PWM (both INT or EXT POT) you cannot really control the frequency. It is hard coded with the logic on board with the potentiometer (either INT or EXT POT). So the only way to control the frequency is to use external PWM (EXT PWM) and generate it yourself.
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Re: MD30C Frequency control

Postby liteace » Mon Jan 08, 2018 5:48 am

ober wrote:. So the only way to control the frequency is to use external PWM (EXT PWM) and generate it yourself.



Thank you for the information, what would be the best to use as external pwm & frequency control, is there any circuit/s you could recommend

Thanks
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Re: MD30C Frequency control

Postby ober » Tue Jan 09, 2018 6:46 am

Well, there are many examples uses microcontroller to generate PWM. Arduino is quite common. As for PWM frequency, if you use Arduino, the default PWM frequency for Arduino UNO is around 500 to 900 Hz, that is good. Yet, we recommend 1KHz to 20KHz.
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Re: MD30C Frequency control

Postby liteace » Tue Jan 09, 2018 7:38 am

Thank you again for the info and the fast support.
I have found a ready built square wave frequency generator with adjustable pwm from 0 - 100% and adjustable frequency 1Hz to 150KHz, I don't think I'll be using the whole frequency range but would that be OK as an input?

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Re: MD30C Frequency control

Postby ober » Tue Jan 09, 2018 8:47 am

Yes Sure, that would be good. Just keep the frequency below 20KHz is good enough.
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Re: MD30C Frequency control

Postby liteace » Tue Jan 09, 2018 10:44 pm

Thanks again, next question, the ready built square wave generator, the output voltage is the same as the input voltage 3 to 30 volts, what is the safe input voltage to use for the MD30C on the external connector?

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Re: MD30C Frequency control

Postby ober » Thu Jan 11, 2018 5:39 am

5V is the safest voltage as most of our setup and many existing customer is using 5V system to control MD30C and further control motor.
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