USB DrDAQ PWM

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M.Yasser
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USB DrDAQ PWM

Post by M.Yasser »

Hi,
I'm trying to use PWM1 and PWM2 of the USB DrDAQ writing my own programs using the SDK. To be able to control motors using H-bridges, I need to raise the voltage level of the PWM signal from about the 0-2V to meet the logic level 0-5V of the H-bridges. so I need some information about the o/p circuit of the PWM. Is it safe to connect a pull-up resistor to the o/p?
Are there any alternative solutions?
Regards.

Martyn
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Re: USB DrDAQ PWM

Post by Martyn »

You will need to amplify the output of the DrDAQ it is a low level signal, pull-up's wont work.
Martyn
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M.Yasser
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Re: USB DrDAQ PWM

Post by M.Yasser »

Hi,
PWM supposed to be a digital signal (on/off) not an analog signal isn’t it?
Analog signals need amplifier if they are small signals; digital signals need a level converter.
I need to know the output circuitry of USB DrDAQ to apply a suitable conversion circuit to it.
Regards.
Yasser

Pico Stuart
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Re: USB DrDAQ PWM

Post by Pico Stuart »

Hi There,

One option would be to use an NPN transistor. Simple and effective.The silicon transistor was invented in 1954 and has been considered one of the greatest inventions in the history of technology. In terms of using the PWM function of DR Daq you could connect the base to the PWM OUTPUT( signal voltage), choose a value of resistor suitable for connecting to the +Ve rail ( 1 K ), connect the emitter to negative (ground) the result collector output will be inverted.
Dr Daq PWM.jpg
Hope this helps,

Have a great weekend.

Kindest regards,

Stuart
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M.Yasser
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Re: USB DrDAQ PWM

Post by M.Yasser »

Hi Pico Stuart,
Thank you for your reply. You gave me a nice inexpensive solution.
Although I wanted to understand the o/p circuitry of DrDAQ.
Thanks again.
Yasser

Martyn
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Re: USB DrDAQ PWM

Post by Martyn »

We do not divulge our IP so we can't provide you with this detail.
Martyn
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M.Yasser
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Re: USB DrDAQ PWM

Post by M.Yasser »

no problem.. thanks any way.

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