Proper setup: 2 fans, Repetier firmware

[dsnettleton]

I just received two fans in the mail for my rostock max. They are both 12V fans. One is a 25mm fan for the PEEK, the other a 40mm fan for the workpiece. I know I'll have to re-adjust my PID settings after installing the fans. I want my 25mm fan to run as long as the hotend is on, and my 40mm fan to run whenever the slicer thinks it should. There are two 12V fan outputs on the RAMBo, and I'm not sure which to use when, or how to set them up properly. I think my real trouble is going to be getting the 25mm fan running all the time. Will I have to adjust my firmware? Also, my PEEK fan has three wires. I understand that the third wire (the white wire) reports the fan speed back to the motherboard. Basically, I plan on ignoring this unless there's a spot on the RAMBo meant to accept the input.

Any advice setting these up will save me a lot of time, and probably be useful to my other forum-going friends.

Thanks,
--dsnettleton

[Polygonhell]

Just connecting the always on fan to 12V is the easy way to do it.
Repetier has a specific fan option for this, where the fan runs anytime the extruder is on or above 50C, however I suspect John doesn't enable it in his firmware. I have it set up in mine on the extruder 2 output, not the fan output.
The primary software driven fan should just work on the first fan output.
You can ignore the additional wire.

[geneb]

I use the Fan #2 connection on the RAMBo for the PEEK fan. In the slicer code prefix, I put in "M42 P6 S255" and that starts the fan when the job is run.

I use Fan #1 as the layer fan - that is controlled (among other ways), by the fan slider in Repetier-Host.

g.

[dsnettleton]

Looks like I was on the right track. I like the idea of starting the PEEK fan manually with G-Code. You guys are great. Thanks.

[Jimustanguitar]

Do you have a shroud or bracket picked out to print for either of these? I'm about to embark on the same modifications and am curious what others are using for their layer fan.

[dsnettleton]

I've been working on my own fan shroud. I'll post it on the forums and thingiverse if I get it working.

[geneb]

I use a very small squirrel cage fan on mine.

g.