SLB Flood Port Trigger with ATC

misquamacus · November 3, 2026, 10:55pm

I have a newly assembled Altmill 4x4 w/ATC and it is working great, but I can’t get it to turn on my dust collector. I have the Flood port wired up to the recommended IOT outlet, but I’m not sure how to actually make it trigger. On my other machine (different brand) I just press the “Coolant” button and the dust collector turns on. Pressing the Flood button in the Coolant menu on this Altmill just drops the tool out of the ATC. Any help would be appreciated.

gwilki · November 4, 2026, 12:46am

@misquamacus Welcome to the group. I don’t know anything about how the ATC is connected or run by your controller. However, in the tech manual, this is what it says about running things connected to the Flood port:

"Flood

If you’ve used a ‘Coolant’ output previously, this 5V output still serves the same function. Simply turn the digital signal on or off using M8 and M9 commands either manually, in g-code using your post processor, or using your g-code sender’s start/end g-code code blocks.

This output is commonly used to automatically control a vacuum or router to turn on/off at the start/end of a job using an IOT Relay. It also can be used for any other purpose with any component that accepts a 5V 40mA digital signal."

KGN · November 4, 2026, 1:27pm

You likely have the event out trigger set to an ATC port.

Once connected, go to Config → Accessory outputs.

You can see the 4 triggers configured ($750 → $753) and the 4 ports ($760->763). These trigger on the firmware side for specific actions, like spindle on, coolant on, etc.

If you have an ATC and have gone through the setup - 3 get set by us (1-3) in P999.macro as part of the ATC configuration wizard if you’ve gone through that.

P999.macro

ef4c60f0e


      
          ; ******** TOOL CHANGER SETTINGS ********
          ; xxxxxxxx GENERAL CONFIG xxxxxxxx
          (print, Applying tool changer settings)
          $485 = 1;       Keep tool number over reboot
          $675 = 3;       Execute M6T0 and Fail M6 if tc.macro is not found
          
          ; xxxxxxxx PIN CONFIG xxxxxxxx
          $370 = 0;       Invert I/O Port inputs (TODO: Not override unrrelated bitfields)
          $372 = 1;       Invert I/O Port outputs (TODO: Not override unrrelated bitfields)
          
          $750 = 7;       Event 1 trigger: Spindle at speed
          $751 = 0;       Event 2 trigger: M62 - M65 only
          $752 = 0;       Event 3 trigger: M62 - M65 only
          
          $760 = 0;       Event 1 port
          $761 = 1;       Event 2 port
          $762 = 2;       Event 3 port
          
          ; ******** HOMING SETTINGS ********
          $44 = 4;        Primary Homing Move
          $45 = 1;        Secondary Homing Move

4 is left alone, and default has it set to M8 (your flood) triggering port 3 - you probably want to disable this and restart your controller after resetting. Set the trigger to none like the ATC macro does for 2 of the other 3.

gwilki · November 4, 2026, 1:36pm

@KGN That’s what I was trying to say.

KGN · November 4, 2026, 1:42pm

Alas “Event port drops my tool out” has come up before with a third party system.

misquamacus · November 4, 2026, 3:17pm

That solved it! Thanks for your help. My experience with the machine, and this software has been great so far. Your documentation and videos are impeccable. That dust collection trigger issue was my only bit of confusion, so it might be worth putting a specific mention somewhere in the ATC documentation.

Thanks again!