Berd-Air - poor pwm response with ez switch
ockray83 last edited by
I recently bought a berd air kit from makerhive to install on my delta printer with a duet 2 wifi. I bought the extra "ez switch" they sell as well, to isolate & protect the duet from the pump. I have everything wired and plumbed and at 100% I'm blown away (no pun intended) at the amount of air this thing pushes through that little cooling ring.
The problem is, I can't seem to control the speeds in between 0 and 100% very well.
Initially I had an awful noise from the pump at anything below about 80%.
After researching this on the forum a bit, I saw people had to change their frequency to the 25k range to get better performance and reduced noise, so I tried that. Now the awful noise is gone, but I don't seem to get a change in the pumps output unless I make a drastic change (more than 50% shift). I've also tried various other frequencies with varying thresholds of poor response and awful noise.
I saw a bunch of berd air posts while researching this, but none that involved the e-z switch I'm using. I'm wondering if the switch is expecting a fan input with switching occurring on the positive lead, while I believe the duet switches the negative pin. Would m106 i1 switch pwm to the positive pin?
For reference, this is an example of the switch, makerhives web page seems broken right now
ockray83 last edited by
It's meant to protect the control board by isolating the fan pwm cconnection from the pump circuit. The ez switch has connections from the psu to the pump on one side and on the other side it takes in a 2 pin 12-24v fan signal from the controller
o_lampe last edited by
Just to be sure, did you check the jumper for the PWM fans is at the 'Vin' position?
Even if we'd know which type of MOSFet it is, we don't know if the optocoupler inverts the signal.
I believe it's common to switch a MOSFet to GND. Switching to Vin requires a bootstrap circuit but I don't see any.
ockray83 last edited by ockray83
@o_lampe The jumper is in the Vin position.
The MOSFet is identified as F5305S
The coupler appears to be an EL817
I'm not certain if that helps at all.
It looks like makerhive sells all their berd air kits with these switch boards now. If this were a common issue I think I would find it in forum posts somewhere. Maybe I have a defective board/pump?
Side note, I did try running a print at 100% speed, just to see what happened and I noticed that while the heated bed output light was illuminated, I got a slight change in pitch from the pump and checking with a meter, the power going to the pump was dropping off by .08vdc and rising back again once the light was out. At the moment the two are sharing the same PSU.
Update: makerhive got back to me and are sending me a new switch, they believe mine is defective. I should get it in a few days.