You can not control both pumps independently but it is possible to use a y-adapter for the PWM signal so both pumps will run with the same settings.

You can also connect the rpm signal of your fist pump to the 4th channel and the signal of the second pump to the third channel. Make sure to use the ground on the aquaero to avoid problems with the electronic.

Hello Chris - it has to be, surely? !!! If it is, I've been following your OCN thread.

If you want to control both (well, all 4) pumps together, so they all run at the same speed, then you can just use a PWM splitter on channel 4. If you then want RPM reports from more than just one pump you'll have to connect them up to the other headers accordingly, so to monitor all 4 pumps you'll use up a whole aquaero worth of headers, but you'll only need the one PWM header to control them all. I do believe people have sometimes had problems splitting PWM to a lot of fans on a rad or similar, since at some point the signal will be too weak to be split again, but for 4 devices I would expect you to be OK, I guess you'll just have to try it.

If you want separate PWM control of each MCP35x2, then you'll need 2 aquaeros, as there's only one PWM output possible. You could try using a voltage to PWM converter on one of the 3-pin headers, but I haven't tried this and don't know enough about it to recommend any particular solution.

Zitat von »Shoggy«

the signal of the second pump to the third channel. Make sure to use the ground on the aquaero to avoid problems with the electronic.

Shoggy, I am about to connect up an MCP35x2 to my aquaero too, and I want to monitor the RPM of both pumps.

Can I just check I've understood correctly - are you saying that for the pump that is connected to, say channel 3, I must connect both the yellow RPM wire and the black ground wire??? The potential of the ground to the aquaero and to the pump are exactly the same anyway, since the pump and aquaero will be connected to the same MOLEX splitter, but if you say it must be connected then of course that is what I'll do.

Yes, exactly that. Ground is always the same but connecting it also to the aquaero fan port you can avoid possible problems.

Great. I just got my 2 MCP35x connected up. I did have a couple of teething problems - max flow didn't increase from what I saw with one pump, and I was seeing reported RPM drops to 0 sometimes. I figured out it was a lack of clean power.

Fortunately, I already had a separate power brick connected to my radbox where the pumps are (for filling and bleeding when the PC is off), in parallel with the power from the PC (with diodes to prevent back-current both ways) so I stuck a relay in to switch the power brick into the circuit when the PC is on, so I now don't get any vdroop to the pumps and they draw power from both the PC and the power brick together. Now I get 20% to 30% more flow than I had on one pump and no more RPM report dropouts.

It looks like these pumps need a fair bit of power, I think the rating is 18w each, if you have any similar problems I'd look first at power, since mine seemed to be working fine and were still pumping OK but were behaving wierd at about 11.2v, they really need a good clean 12v feed.

Oh, and I remembered something else - when I've read about people having trouble splitting a PWM feed too many ways (with resultant attenuation of the signal) I have seen mention of using a Scmitt trigger to amplify/repeat the PWM signal. Hopefully you'll have no problem splitting the feed 4 ways, but if you do that's worth looking in to.