# Both dust collection auto on/off (wood) and air blast auto on/off (alum/plastic)

**URL:** https://forum.onefinitycnc.com/t/both-dust-collection-auto-on-off-wood-and-air-blast-auto-on-off-alum-plastic/19568
**Category:** Accessories
**Created:** [March 21, 2023, 11:18pm UTC](https://forum.onefinitycnc.com/t/both-dust-collection-auto-on-off-wood-and-air-blast-auto-on-off-alum-plastic/19568 "2023-03-21T23:18:49Z")
**Posts on this page:** 1
**Showing post:** 4

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### Author: ![349iq2345](https://avatars.discourse-cdn.com/v4/letter/3/bb73d2/32.png) [@349iq2345](https://forum.onefinitycnc.com/u/349iq2345)
#### Post date: [March 22, 2023, 2:52am UTC](https://forum.onefinitycnc.com/t/both-dust-collection-auto-on-off-wood-and-air-blast-auto-on-off-alum-plastic/19568/4 "2023-03-22T02:52:12Z")

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Hey Martin,

> [@Best way to e-stop spindle and VFD?](https://forum.onefinitycnc.com/t/best-way-to-e-stop-spindle-and-vfd/10792/30):
>
> ![Hitachi_WJ200_Manual__4-7_Control_Logic_Signal_Specifications_PDF210_cropped1_AL_outputs_highlighted](https://us1.discourse-cdn.com/flex022/uploads/onefinitycnc/original/2X/a/a613dc31c805307676b2ece55798208a96f826df.png)
> 
> As you can see there is a **minimum load current** and that is a sure sign that it is a [solid state relay](https://en.wikipedia.org/wiki/Solid_state_relay). Unlike [electromagnetic relays](https://en.wikipedia.org/wiki/Relay), a solid-state relay can only hold its state when a minimal load current is flowing. That’s because they’re not really switches, they’re thyristors (a specific type of semiconductor).

A spindle coolant pump or [cooling station](https://www.spindel-shop.de/de/Kuehlung/Kuehlgeraete/Kuehlgeraet-KG5000.html) should be in the range of the AL0..2 outputs (you can try it out if it stays on with its current), but surely not a dust extractor, since either when connected directly it is much too strong for this output or when connected with an [external relay](https://forum.onefinitycnc.com/t/tool-enable-m15-breakout-board-auto-turn-off-on-router/720), usually the relay’s control input can not ensure the minimal current (see the table above).

> [@MVall](#):
>
> > [@349iq2345](#):
> >
> > What do you mean with postprocessor?
> 
> Well, my thought was to make roughly 3 post processor versions in Vectric: 1) for wood products in which the dust collector switches on (basically the normal post processor); 2) for alum/plastic which includes M7 command for air blast and somehow switches off dust collector; 3) for laser which includes M8 to turn on fume extraction and air assist (I don’t need flood coolant. Just want to trigger Load 2).

Ah, okay, with postprocessor you really mean postprocessor 🙂 I understand better what your plan is.

> [@MVall](#):
>
> I don’t think the VFD dust collector would come in to play with the laser because you have to switch from VFD to PWM spindle under tool configuration first.

Yes.

> [@MVall](#):
>
> By the way, I planned on having the Load 1 and Load 2 pins trigger external relays.

This is necessary since unlike the load-1 and -2 outputs on the original [Buildbotics.com](http://Buildbotics.com) Controller, on the Onefinity Controller they are only able to provide small currents.

> [@MVall](#):
>
> > [@349iq2345](#):
> >
> > Would the solution that when one of the workpiece coolants is activated (with M7 of M8 commands), this makes the dust collection staying off be satisfying?
> 
> Yes, very satisfactory. Thanks much. I somewhat wondered if that were possible, but I’ll have to look at the manual again to see how that would work. VFDs are pretty cool devices 🕶 I believe the VFD input method would be better than using outputs, which I’m pretty much out of.

Since I didn’t have this use case yet, I am not sure at the moment which output function you would select to feed the second input of the logic (besides “run signal” or “frequency arrival signal” on the first). But you have the manual to and can have a look. I got to leave now until tomorrow evening.

> [@MVall](#):
>
> > [@349iq2345](#):
> >
> > As far as I remember the ‘tool-enable’ pin (usually M3 command on PWM spindles/router) does not work when a VFD is selected as tool, but I got to look if this is true.
> 
> Ok, well I’m using the laser as a PWM spindle, so maybe I could trigger a relay for laser fume extraction and air assist through tool enable instead? And keep Load 2 free? (assuming there isn’t communication to VFD to turn on dust collection, of course)

Of course, since when ‘tool-type’ “PWM spindle” is selected (or the new ‘Laser’ and ‘Router’ tool-types as of firmware version 1.0.9, which internally still rely on the PWM spindle entry but with a few options invisibly selected), you have the ‘tool-enable’ pin that is triggered by the M3 command, and you can trigger more than one device from this output.

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