IOT Relay Wiring Diagram

Maybe they are trying to keep the costs down.

[quote=“360icon, post:14, topic:29883”]

Hooked it up and it worked perfect first time in Easel!! - then… the next day it no longer will trigger dewalt with the exact same setup as the night before?? - tried another project sending gcode thru picsender and works perfect overtime again - so whats up with that i wonder??

1 Like

Quick question.
In Scott’s post above I see he has the relay connected to the 0-10v spindle control. While I can’t seem to find the post now, I’ve also read that you should connect it to the PWM output instead. Can anyone provide any clarification?

1 Like

I have the JTech Laser connected to the PWM (Pulse Wave Modification) connection because that’s a digital signal connection to transmit variable level codes to the laser (10%, 50%, 100%, etc). I suppose some folks might use the PWM with spindles that allow for that transmission to control spindle speeds. With the IOT and the Dewalt 611 Router I think all spindle speed is controlled via the variable dial on the Dewalt. Or at least that’s how I perceived it as happening.

The basic IT question is if it worked yesterday and today it doesn’t what have you changed in the interim. My guess is that with the installing of Picsender and maybe their version of Grbl you’ve changed some of the stored codes/variables in Grbl on the Arduino board in the X-Controller. I know when I flashed my X-Controller to their 1.0c version of Grbl that all my X-Y-Z movements were hosed. Some work (and changing my wires for my Z axis) and I’m back up and running. Easel is great because it makes everything simplistic but at the same time it hides from us all the software settings that are taking place in the background. I myself am still learning these and I’m still working on getting my Dewalt spindle control back through the IOT now that I’ve got the laser and my X-Y-Z movements correct.

If you use the PWM output for triggering the relay then your G-code has to set the spindle speed to the maximum allowed by the setting in grbl (in config.h) for versions prior to 1.0c. For 1.0c the spindle speed would have to be set to the maximum value as set in the $30 parameter or greater to get the relay to turn full on.

With the 0-10 volt output you only have to set the spindle speed high enough to output 3.3 volts or greater to get the relay to turn full on.

Another way to look at it is the Pulse Width Modulation looks like pulsing DC (on/off/on/off etc) where the 0-10 volts is a steady DC signal. When using the PWM output you have to set the spindle speed high to get a steady DC voltage out of the PWM output.

A small difference, but it might be useful information for someone.

1 Like


Sorry for your difficulties. The firmware and documentation references are here.

No worries Larry and ‘difficulties’ is what is forcing me to learn how these systems interact (hardware & software). Overall I’m thrilled with how things are going and a learning curve is to be expected with these systems. We aren’t buying off the shelf integrated systems. If we were the price would be higher and the expectations to go along with it.

1 Like

Based on Phil’s comment, it seems prudent to have separate IOT relays for the DeWalt router and the dust collector. Given that, can the output from the X-Controller 0-10v output support 2 IOT’s in parallel (thus increasing needs amperage while keeping voltage constant)? And to be sure, 0-10v is the preferred connection point?

While an old thread, seems like a wise place to ask…



Both the PWM and 0-10volt outputs are dependent on the spindle speed setting to have a TTL like signal to drive the IoT relay input. Assuming you select S0 for relay off and S12000 or greater (grbl versions less than 1.0c) and S greater than the value in $30 (rpm max) for versions 1.0c and above for relay on — the following comments apply.

You can draw up to 40mA from the PWM signal and 30-40mA from the 0-10volt signals from the X-controller without causing any problems.

I have been told (I don’t have one) that the IoT relay has a transistor stage in the control input circuit. If that is true then you could most likely run two IoT relays off of either the PWM or 0-10volt outputs of the X-controller.

The PWM and 0-10volt signals are logically connected internally. You could run one IoT relay off the PWM and one off the 0-10volt signal if you are concerned about the load.

SO it’s time for me to add my experience here just to emphasize the importance of following the sage advice found here.

Ordered my IOT Relay - the one referenced here from Amazon.
Did the wiring and the tests and zero.

Used a 9 volt battery to check the IOT relay - A OK
Disassembled by X-Controller and pushed on all the ribbon cables - one seemed to move a bit.
Reassembled the X-Controller and Bingo Router control works.

Also I ordered a second IOT Relay to run my Shop Vac.

Well worth the cost for the convenience and the insurance.

Hope this helps some other neophyte like me


1 Like

Hey everyone-

I have this same setup using the IoT, dewalt spindle, and x-controller. I have installed the IoT with the + going to the 0-10volt and the - going to the ground as it should.

What I am having an issue with is that when I test the spindle using easel, it turns on for a very short burst and then the relay switches, the spindle stops, and then easel resets like it lost USB connection. I have to start the carve process all over again and the same thing happens again. Kind of like it is getting some kind of power kick back to the x-controller that is causing the x-controller to reset.

Any help with this would be greatly appreciated.


Hi Phil-

Nope, I have the x-controller plugged in separately. The only thing plugged into the IoT is the spindle.


I just tried this and the same issue occurs. I get a quick power-on of the spindle, not even enough to get to speed, and then it basically acts as though the USB is disconnected from the x-controller and reconnected.

So, when the disconnect occurs, I’m not seeing anything in machine inspector

Nope, I have the x-controller plugged in separately. The only thing plugged into the IoT is the spindle.

I’ll check this out when I get home. I am curious about the max rpm setting

Larry’s grbl

Do you have any further info on how to do this?

Hi to All!

Sorry for off-topic.
Am I understand correctly, than if I would like to use X_Carve controller to control the spindle on/off,it couldn’t be done just with X-Carve controller - I should use some “outer” relay?
Is there any manual about connectors I should use for that, and about voltage on them?
(I live in Europe, we’re using 220V - if that is need to be mentionned :slight_smile: …)

Thank you in advance.

Thanks for reply.
If you mean that post (missed that before):

Will try that today.