0-10v PWM

[shaikh]

Hi all,

I need to control a fan via PWM from a raspberry pi.
The PWM on the fan states "PWM - 10V min". I assume this means it requires a 10v PWM signal. What is the best way to accomplish this using a pi as the GPIO pins will be 3.3v.


I have attached the information from the fan supplier in which it states a 10v PWM is required.

Thanks

[scotty101]

A transistor or optoisolator where the 'output side' is connected to 10v.
Or a logic level converter

Given the mains voltages involved, i'd go for the optoisolator option.

[shaikh]

Thanks for the reply.

I don't have any experience in optoisolators.
Am i correct in saying that the optoisolator will basically act as a switch, switching the 10V 5ma supply creating a 10v PWM .

Thanks

[scotty101]

Am i correct in saying that the optoisolator will basically act as a switch, switching the 10V 5ma supply creating a 10v PWM .

Essentially yes. The 3.3v output from a GPIO pin is passed in to the optoisolator powering an LED, this LED triggers a light sensitive transistor allowing current to flow through it. Treat it like a transistor.

[shaikh]

Will this be able to cope with the 1 - 10kHz PWM frequencies?

Would this also be the case with a transistor? Would they cope with the PWM frequencies.

Thanks

[scotty101]

Probably. You'd need to check with the specific datasheet to confirm. 10KHz isn't that fast.

[rpdom]

Pretty much any optoisolator will cope with 10KHz. I've just checked a few datasheets on common types and they can all handle it.