# Laser on/off control in gSender reversed

**URL:** https://forum.sienci.com/t/laser-on-off-control-in-gsender-reversed/25183
**Category:** 🔥 Laser
**Created:** [December 14, 2025, 5:02pm UTC](https://forum.sienci.com/t/laser-on-off-control-in-gsender-reversed/25183 "2025-12-14T17:02:12Z")
**Posts on this page:** 8
**Page:** 1

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### Author: ![jimzdrojewski](https://forum.sienci.com/letter_avatar_proxy/v4/letter/j/e9a140/32.png) [@jimzdrojewski](https://forum.sienci.com/u/jimzdrojewski)
#### Post date: [December 14, 2025, 5:02pm UTC](https://forum.sienci.com/t/laser-on-off-control-in-gsender-reversed/25183/1 "2025-12-14T17:02:13Z")

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In gSender, under the spindle/laser tab, the controls for the laser on/off are reversed. When I click on, it wil turn the laser off and when I click off, it will turn the laser on. How do I switch that around? Is there a config setting for that?

Also, the on/off controls work normally for the spindle.

Thanks!

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### Author: ![whitewolf](https://forum.sienci.com/user_avatar/forum.sienci.com/whitewolf/32/7626_2.png) [@whitewolf](https://forum.sienci.com/u/whitewolf)
#### Post date: [December 14, 2025, 5:57pm UTC](https://forum.sienci.com/t/laser-on-off-control-in-gsender-reversed/25183/2 "2025-12-14T17:57:05Z")

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Is this a new setup or did it work correctly previously?  
What version of gSender are you using? I’m running 1.5.5 (and earlier version) and do not have this issue.

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### Author: ![gwilki](https://forum.sienci.com/user_avatar/forum.sienci.com/gwilki/32/366_2.png) [@gwilki](https://forum.sienci.com/u/gwilki)
#### Post date: [December 14, 2025, 8:02pm UTC](https://forum.sienci.com/t/laser-on-off-control-in-gsender-reversed/25183/4 "2025-12-14T20:02:59Z")

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@jimzdrojewski What is your $743 setting? To find it, enter $$ in console and scroll down to 743.  
You are running a LongMill 2.5 on an slb controller, correct?

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### Author: ![jimzdrojewski](https://forum.sienci.com/letter_avatar_proxy/v4/letter/j/e9a140/32.png) [@jimzdrojewski](https://forum.sienci.com/u/jimzdrojewski)
#### Post date: [December 14, 2025, 8:29pm UTC](https://forum.sienci.com/t/laser-on-off-control-in-gsender-reversed/25183/5 "2025-12-14T20:29:39Z")

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New setup. I’m on version 1.5.3

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### Author: ![jimzdrojewski](https://forum.sienci.com/letter_avatar_proxy/v4/letter/j/e9a140/32.png) [@jimzdrojewski](https://forum.sienci.com/u/jimzdrojewski)
#### Post date: [December 14, 2025, 8:31pm UTC](https://forum.sienci.com/t/laser-on-off-control-in-gsender-reversed/25183/6 "2025-12-14T20:31:47Z")

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$743 = 3

Yes to Longmill 2.5 with SLB.

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### Author: ![gwilki](https://forum.sienci.com/user_avatar/forum.sienci.com/gwilki/32/366_2.png) [@gwilki](https://forum.sienci.com/u/gwilki)
#### Post date: [December 15, 2025, 12:31am UTC](https://forum.sienci.com/t/laser-on-off-control-in-gsender-reversed/25183/7 "2025-12-15T00:31:26Z")

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@jimzdrojewski I am running gSender 1.4.12 so take this for what it’s worth. #743=0. You may want to try that. Nothing to lose, I think. Your call though.

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### Author: ![jimzdrojewski](https://forum.sienci.com/letter_avatar_proxy/v4/letter/j/e9a140/32.png) [@jimzdrojewski](https://forum.sienci.com/u/jimzdrojewski)
#### Post date: [December 15, 2025, 3:23am UTC](https://forum.sienci.com/t/laser-on-off-control-in-gsender-reversed/25183/8 "2025-12-15T03:23:19Z")

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Thanks! That’s what I ended up doing. I also flipped the switch on the PWM option that was along side it in the GUI…not sure of the number. So far it seems to be working correctly for now.

Now to just get the offset straightened out…there’s always tomorrow!

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### Author: ![gwilki](https://forum.sienci.com/user_avatar/forum.sienci.com/gwilki/32/366_2.png) [@gwilki](https://forum.sienci.com/u/gwilki)
#### Post date: [December 15, 2025, 12:37pm UTC](https://forum.sienci.com/t/laser-on-off-control-in-gsender-reversed/25183/9 "2025-12-15T12:37:20Z")

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