# SLB Flood Port Trigger with ATC **URL:** \ **Category:** ❓ Question\ **Created:** [November 3, 2026, 10:55pm UTC](https://forum.sienci.com/t/slb-flood-port-trigger-with-atc/27581 "2026-11-03T22:55:03Z")\ **Posts on this page:** 1\ **Showing post:** 5
**Author:** ![KGN](https://forum.sienci.com/letter_avatar_proxy/v4/letter/k/c77e96/32.png) [@KGN](https://forum.sienci.com/u/KGN)\ **Post date:** [November 4, 2026, 1:42pm UTC](https://forum.sienci.com/t/slb-flood-port-trigger-with-atc/27581/5 "2026-11-04T13:42:09Z")
Alas “Event port drops my tool out” has come up before with a third party system. > [@Gsender turning on Switch when spindle activates](https://forum.sienci.com/t/gsender-turning-on-switch-when-spindle-activates/25461/2): > > So you didn’t include any relevant information about your hardware setup here but I’m going to use the assumption that you are using some sort of grblHAL device. It’s possible that you have an event linked in your firmware configuration to a specific AUX pin for the spindle on trigger (M3/M4) If you’re using SienciHAL (SLB or SLB-EXT without having flashed a more recent version of grblHAL): You need to check that whatever port your ATC switch release is set to does not trigger on M3/M4. This… --- _[View the full topic](https://forum.sienci.com/t/slb-flood-port-trigger-with-atc/27581)._