PWM Control Question
Hello, I just picked up a PDM 15 and while configuring the outputs I noticed a large red triangle saying not to PWM any device drawing more than 10A during normal operation. I have 3 items that I am pretty sure pull >10A in normal service, but I have not datalogged them yet.
1st items are 2x SPAL 30102800HO fans and the other item is a Weldon 2025-A fuel pump.
The fans I wanted to use PWM to slowly ramp up the duty cycle as engine temp rises. I had originally planned on using 2 outputs for each fan. SPAL documents show anywhere from 24.5A-35.8A draw depending on static pressure. I doubt I am anywhere near that max static pressure as it would be almost no airflow. Worst case is probably 30A each.
The 3rd item is the Weldon 2015-A fuel pump which, according to the datasheet that came in the box, can pull close to 16-17A around 50 PSI. For the fuel pump I planned on initially using simple RPM > 2500 = 100% duty. But later on I wanted to use MAP or injector duty cycle to determine the PWM output.
Long way to get to my question, is 2 output pins per device enough to be able to use PWM? If I have to go to 3 I'll need a PDM25 making this newly purchased PDM15 a paperweight.
Support tolds me, that I can use more outputs for more than 10A. So you can try use SSR. PDM25+ can set up to 400Hz frequency so it can be better.