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[Steve W]

Greetings from Southern California !!

A newbie here - so please excuse me if this has been discussed previously.  and Happy New Year.

I'm resto-modding a vintage GMC motorhome and am designing a PID controlled engine cooling system based upon an electronically controlled viscous clutch fan from a Mercedes Sprinter van.  Clutch engagement - and hence fan speed - can be controlled via PWM.  My research so far suggests that the desired frequency for said PWM control is 20Hz.

Might anyone know of a PID controller - just like the SYL-1612 - preferably an Auber - with the ability to run at 20Hz (cycle rate) ??  I haven't experimented yet - but I'm expecting that the 1612's .5Hz (minimum 2 second cycle rate) is gonna be too slow.

Thanks in advance for your comments, suggestions, and questions.

Steve W

[Kkane]

SYL-1612 only has two outputs: DC SSR output and mechanical relay output. Its default output is time proportional PWM mode, and recommended cycle time is 2s for SSR and 20s for relay output. You can set at least 1s as the output cycle time. This controller doesn't have a traditional PWM output as your requirement. 20Hz means 50ms cycle time, which could be too fast for this controller.

For your case, you may need a specialized PWM controller or PLC. Or you can consider an open source controller like Raspberry PI. 

[Steve W]

Thanks Kkane !!

I'm a bit hesitant to travel down the Raspberry PI / Arduino paths - kind of like opening Pandora's box - but they're probably the best solution.

I'm also considering use of the 1612 as a bang/bang on/off control - and when "on" - feeding that voltage into a signal generator and manipulating the frequency / PWM manually.

Nothing like over engineering a simple radiator fan cluch eh ??

Thanks again,
Steve W

[Kkane]

If you don't need precise temperature control on this fan, simple ON/OFF mode should be fine by using its relay output. It can be turn on when temp is high and off when temp is low.

[Steve W]

Thanks Kkane -

And you're 100% correct.

I have the setup wired and operating as you suggest - with a temperature controlled on/off relay.

The fan is surprisingly powerful - and sounds like a jet engine - especially upon startup.  Hence my desire to "soft start" it at a reduced speed and ramp up as necessary.

And also doing it - simply - because we can 

SW