# Confused about using the THC with Plasma Cutters that don't have a CNC Port **URL:** \ **Category:** General Discussion\ **Created:** [June 19, 2023, 6:06pm UTC](https://forum.arcdroidcnc.com/t/confused-about-using-the-thc-with-plasma-cutters-that-dont-have-a-cnc-port/3002 "2023-06-19T18:06:09Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![StevenM](https://avatars.discourse-cdn.com/v4/letter/s/d6d6ee/32.png) [@StevenM](https://forum.arcdroidcnc.com/u/StevenM)\ **Post date:** [June 19, 2023, 6:06pm UTC](https://forum.arcdroidcnc.com/t/confused-about-using-the-thc-with-plasma-cutters-that-dont-have-a-cnc-port/3002/1 "2023-06-19T18:06:10Z")
I’ve been trying to find information about Voltage Dividers, breakout boards, etc. that would be aftermarket components to allow using the ArcDroid under THC control. I’m not really clear on what is needed to make this happen. I do see there are some folks that are offering their version of voltage dividers even for those Plasma Cutters that have a CNC port built in. Appears to be related to developing voltage dividers because the onboard ones are sub-par. Anyway, just have a revamped Votage divider surely can’t be all that’s needed. Anyone care to provide some insight? Thanks in advance, Steven M ---
**Author:** ![Amp\_Mechanic\_JB](https://avatars.discourse-cdn.com/v4/letter/a/ea666f/32.png) [@Amp\_Mechanic\_JB](https://forum.arcdroidcnc.com/u/Amp_Mechanic_JB)\ **Post date:** [June 20, 2023, 3:10am UTC](https://forum.arcdroidcnc.com/t/confused-about-using-the-thc-with-plasma-cutters-that-dont-have-a-cnc-port/3002/2 "2023-06-20T03:10:59Z")
You can wire a voltage divider right off the + and - lugs on your plasma cutter. The arc voltage gets divided so the THC input circuit on your CNC can read and adjust torch height up or down as the arc voltage changes. Simple as that. The Arcdroid already has everything needed, you just need to send it a reduced version of the arc voltage, 50:1 is the recommend. Even up to 100:1 will work. I did build and sell a bunch of adjustable voltage dividers with some extra protection and smoothing added into the circuit. With the current firmware updates, a basic voltage divider ( 2 resistors) may work. That’s usually what’s in most plasma cutters with CNC ports that have divided voltage but results may vary. ---
**Author:** ![StevenM](https://avatars.discourse-cdn.com/v4/letter/s/d6d6ee/32.png) [@StevenM](https://forum.arcdroidcnc.com/u/StevenM)\ **Post date:** [June 20, 2023, 3:17am UTC](https://forum.arcdroidcnc.com/t/confused-about-using-the-thc-with-plasma-cutters-that-dont-have-a-cnc-port/3002/3 "2023-06-20T03:17:03Z")
Thanks for the response! I attempted to reach out to you via your website using its email address for contact. I had asked you in the email when you expect the next batch to be available as you are currently sold out. ---
**Author:** ![Amp\_Mechanic\_JB](https://avatars.discourse-cdn.com/v4/letter/a/ea666f/32.png) [@Amp\_Mechanic\_JB](https://forum.arcdroidcnc.com/u/Amp_Mechanic_JB)\ **Post date:** [June 20, 2023, 3:33am UTC](https://forum.arcdroidcnc.com/t/confused-about-using-the-thc-with-plasma-cutters-that-dont-have-a-cnc-port/3002/4 "2023-06-20T03:33:55Z")
hmmm…I don’t see any emails, nothing in my spam folder. Sorry about that Steve. Now, I’m curious as to what may have happened to it. Anyway, I got extra boards made while filling a large order for a company. I just have to order more components and I can make some more. I’ll try and get on that this week. I’ll message you my email address. ---
**Author:** ![StevenM](https://avatars.discourse-cdn.com/v4/letter/s/d6d6ee/32.png) [@StevenM](https://forum.arcdroidcnc.com/u/StevenM)\ **Post date:** [June 21, 2023, 5:51pm UTC](https://forum.arcdroidcnc.com/t/confused-about-using-the-thc-with-plasma-cutters-that-dont-have-a-cnc-port/3002/5 "2023-06-21T17:51:56Z")
> [@Amp\_Mechanic\_JB](#): > > You can wire a voltage divider right off the + and - lugs on your plasma cutter. The arc voltage gets divided so the THC input circuit on your CNC can read and adjust torch height up or down as the arc voltage changes. I read somewhere else that you stated the connections **from** the voltage divider go into the Aux2 connections on the back of the ArcDroid. Also read that you may or do need a code from ArcDroid to enable the THC functionality. So I my mind’s eye there’s connections to the (+) & (-) lugs of the Plasma cutter which go to the Voltage Divider, then out to the Aux2 on the ArcDroid. And nothing more hardware wise is needed. Only adjustments to Gain settings, etc. A simple schematic would be useful. Not details of your PCB, just Plasma → VD → ArcDroid. TIA ---
**Author:** ![Amp\_Mechanic\_JB](https://avatars.discourse-cdn.com/v4/letter/a/ea666f/32.png) [@Amp\_Mechanic\_JB](https://forum.arcdroidcnc.com/u/Amp_Mechanic_JB)\ **Post date:** [June 21, 2023, 6:21pm UTC](https://forum.arcdroidcnc.com/t/confused-about-using-the-thc-with-plasma-cutters-that-dont-have-a-cnc-port/3002/6 "2023-06-21T18:21:20Z")
Correct. Andrew will send instructions with your unlock code, if they are still doing that. Just email ArcDroid with your serial number. I email an instruction PDF when I mail out voltage dividers. Should have info for you by Friday as to when the next batch will be available. ---
**Author:** ![Amp\_Mechanic\_JB](https://avatars.discourse-cdn.com/v4/letter/a/ea666f/32.png) [@Amp\_Mechanic\_JB](https://forum.arcdroidcnc.com/u/Amp_Mechanic_JB)\ **Post date:** [June 26, 2023, 6:51pm UTC](https://forum.arcdroidcnc.com/t/confused-about-using-the-thc-with-plasma-cutters-that-dont-have-a-cnc-port/3002/7 "2023-06-26T18:51:06Z")
Another run of voltage dividers is underway, just waiting on parts. I’ll likely open up pre-orders later this week. I will let you know. ---
**Author:** ![StevenM](https://avatars.discourse-cdn.com/v4/letter/s/d6d6ee/32.png) [@StevenM](https://forum.arcdroidcnc.com/u/StevenM)\ **Post date:** [June 26, 2023, 7:22pm UTC](https://forum.arcdroidcnc.com/t/confused-about-using-the-thc-with-plasma-cutters-that-dont-have-a-cnc-port/3002/8 "2023-06-26T19:22:06Z")
Thanks! I’ll be on the lookout for the notice. ---
**Author:** ![Amp\_Mechanic\_JB](https://avatars.discourse-cdn.com/v4/letter/a/ea666f/32.png) [@Amp\_Mechanic\_JB](https://forum.arcdroidcnc.com/u/Amp_Mechanic_JB)\ **Post date:** [July 14, 2023, 3:01pm UTC](https://forum.arcdroidcnc.com/t/confused-about-using-the-thc-with-plasma-cutters-that-dont-have-a-cnc-port/3002/9 "2023-07-14T15:01:18Z")
Another batch of dividers are up for sale again. Shipping should start next week.[https://www.ampmechanic.com/adjustablevoltagedivider](https://www.ampmechanic.com/adjustablevoltagedivider) ---
**Author:** ![StevenM](https://avatars.discourse-cdn.com/v4/letter/s/d6d6ee/32.png) [@StevenM](https://forum.arcdroidcnc.com/u/StevenM)\ **Post date:** [July 15, 2023, 1:34pm UTC](https://forum.arcdroidcnc.com/t/confused-about-using-the-thc-with-plasma-cutters-that-dont-have-a-cnc-port/3002/10 "2023-07-15T13:34:23Z")
Yay! Placed my order late yesterday evening.