Ortur LM3 I/O Port

I’m looking ahead to a new laser, and the OLM3 is looking pretty promising. One puzzle, however is about the I/O port on the machine. Ortur uses that port to run an exaust fan and a light in their proprietary enclosure.

Since the fan and light seem to otherwise run off a simple switched 12VDC power supply, is this really an input/output port, or is it simply a power port that is switched by the main board? If it is just 12VDC coming off the main board, it can’t supply much power unless there is some additional circuitry and possibly heat sinks on that mainboard. Also, from the pictures I’ve been able to find, I can’t tell exactly how many connector pins are being used in the I/O port. In some pix, it looks like 3, while in other pix it almost looks like more pins. It’s very confusing, and Ortur seems to have exactly zero documentation about this port, other than their instructions to plug the fan and light wires to this port.


Some months ago, I tried to figure out how to use this I/O port to power a fan and a led strip in my laser enclosure. But I finally drop the idea because I did not find a compatible connector that I could plug on.

But here below is what I discovered about this topic if it can help someone. Of course, double check what is written below, I am not responsible if you fry your Ortur Laser Master 3 :slight_smile:

When you look at the I/O port with the reset button on the left, you should have this pinout:

Then you can send M12, M13, M14 and M15 command to change the state of the pins 1 and 6.

Ortur doc says that:

But on my notes I wrote that behavior of these commands is reversed for my OLM3 compared to how Ortur described them, so to be checked on your side.

I also wrote that:
M12, M14 commands make the corresponding pin (1 or 6) voltage switch from 14V to 0V
M13, M15 commands make the corresponding pin (1 or 6) voltage switch from 0V to 14V

And as you said already , I also think you cannot draw too many power from this I/O port.

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Thank you for that very enlightening reply!

It pretty well confirms that you could use those pins (1 and 6) to control relays for other devices that might draw more power than the I/O port can deliver.

Were you able to test the M7, M8, and M9 commands to see if any of the pins change state?

I did the test a few seconds ago: M7, M8 and M9 are rejected, unsupported by the OLM3.

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Thank you for that! Perhaps a future firmware update from Ortur will enable the usual “standard” air-assist GRBL commands.

At least we know of two outputs that have the potential of being used to switch relays for external devices like lights, exhaust fans, and air assist. Although Ortur offers the first two of these with their proprietary enclosure, I consider that lighting and exhaust system to be barely adequate. If I do go ahead to get the LM3, one of the first things I will be doing is to cobble together a control box to switch a better light, and to simultaneously switch both the exhaust fan and the air-assist; an easy thing to do with 2 or 3 common 12VDC-120VAC relays. Hopefully I can locate an appropriate connector to mate with the I/O port.

That port is still a bit of a puzzle… it makes one wonder what future plans Ortur has for that port, and what power load those two 24V pins might be able to support.

In case you decide to go with the OLM3, if one day you find the exact connector name that properly plugs into this I/O port, I am interested :slight_smile:
The only solution I found was to open the aluminium frame (it is easy to do) and remove the connector to solder something else (wires or other connector). But I did not do this as I did not want to void the warranty.

I fully understand the warranty issue.

Sometime in the past few months I ran across a website that specialized in that sort of connector, as well as the tools used for crimping the wires to the contacts. Unfortunately, I cannot remember what search terms I used. In any event, when searching, you need to know the pitch (spacing between) the pins, the pin length, and possibly the diameter of those pins. With that, it’s a matter of searching through the images to find the one that matches the connector configuration.

A thought… I don’t know the size of the pins involved, nor their spacing, but it is possible that you could use something like this: Premium Female/Male 'Extension' Jumper Wires - 20 x 6 : ID 1954 : $1.95 : Adafruit Industries, Unique & fun DIY electronics and kits to use for connecting to those pins and giving you leads that you could solder to. There are multiple sources for these in addition to the one linked.

Yep I had such cables in stock when I did my tests and I tried them but they really do not hold very well in the I/O port.
I mean for testing purpose, they are ok, but for daily use, I am not so sure.

Ah, well… At least you could use them for test leads.

I was finally able to find a connector reference page that has a nearly overwhelming discussion about the many different types of connectors as well as the tools needed to crimp them and even to extract the connectors from their sockets.


Can you get a “replacement” cable from Ortur?

Thanks for this. Can you find out more about the two 4-pin plugs labeled C and Z? It’s part of the pigtail by the laser module. Maybe they could power a fan.

Thanks for the link. I checked it but was not able to identify a matching connector.
I found this website also (Connector identification online - The electronic connector book). It can help for connector identification, but I was also not able to find the exact connector needed.

But honestly, now, I have a standard switch on my air extractor cable and a dimmer switch for my air assist. So no need to bother with all that anymore, I just use my hand to activate the switches :smiley: :smiley:

I do not have a lot of time at the moment to investigate more on this topic. But I am pretty sure the Z plug should allow you to control a motorized Z axis.
For the C plug, I do not know what it could be used for, but I can tell you it has only 3 pins inside, not 4.

Maybe you can try to ask Ortur support directly. When I contacted them about another topic I quickly received an answer.


I’ve pretty much come to the same conclusion myself, though I’ll probably do it the other way around… a dimmer switch on the extraction fan, and a simple switch for the air assist. The extractor fan is a bit more powerful than I need (rated 220 cfm), and the air assist runs off a DC transformer and has its own adjustment knob.

Sometimes the simple way is the best.

Thanks for this topic - I have NOT connected the wiring up, but did find the connectors to use that would operate a SS relay to activate the air pump.

These are the cables I ordered from www.aliexpress.com ( https://tinyurl.com/msxbphsh ) select the 2X3 pin connector to have the 6 pins.

Sono un ignorante in materia di collegamenti. Mi puoi indicare quale relè hai comprato , da dove
e come hai fatto i collegamenti, ti ringrazio in anticipo!

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