LINKS to MESA store (for the items mentioned) are below in this comment! Kudos and many thanks to both Ryan, the founder of V1 Engineering (@vicious1 on the V1E forum), and Kyle (@kd2018 on V1E forum) for their invaluable help. In fact, both Ryan and I used, as guidance, Kyle's immensely helpful plasma build thread which includes many tutorial type posts including both wiring schematic and LinuxCNC software setup info and help. In response to questions in comments about the links for the MESA items, and whether or not a MESA card is available for 1:1 ratio where the plasma machine has no voltage divider, see below. Also regarding questions of whether or not MESA makes a card that does both control of steppers and THC (torch height control), to my knowledge two cards are required, one for each. Kyle used MESA 7i96 for stepper control and MESA THCAD-10 for torch height control. My setup is similar, but I am using MESA 7i96S and MESA THCAD-2. All these setups also require some device (usually a used laptop) running LinuxCNC. A touchscreen type laptop is helpful, but not a necessity. MESA previously sold one THC A-to-D card for 1:1 ratio (THCAD-300), and two for divided (reduced ratio), a 5v option (THCAD-5) and 10v option (THCAD-10). The new THCAD-2 is able to emulate either a THCAD-5 (5v option) or a THCAD-10 (10v option) based on a jumper setting! So its ability to go either way seems to be the reasoning behind the "2" in its name. WHICH RESISTER IS THAT? SEE HERE: Finally, if you have a plasma machine with 1:1 ratio (no voltage divider) and you should find yourself wanting to reduce the voltage yourself in order to use a THCAD other than 300, either 5v, 10v, or a "2" acting as a 5v or a 10v, then per Peter, the founder of MESA (to me via email when I bought a THCAD-2 instead of THCAD-300): "You could return the THCAD2 card for credit and re-order a THCAD-300. Another option would be to add an external resistor to the THCAD2 in the negative lead, say 2.4M for 250V full scale. For safety this should be a HV resistor like: www.digikey.com/en/products/detail/vishay-beyschlag-draloric-bc-components/HVR3700002404FR500/719541 The 250 range improves the resolution somewhat (and continuous overvoltages up to 1000V are no problem)." The following are copied and pasted from my replies in comments, placed here so I can pin this to the top. Happy making! The Mesa board that I show inside the control box, 7i96S, is the one that controls the stepper motors. The only thing the Mesa THCAD-2 does is monitor & control the torch height. Mesa does indeed sell a torch height control board that can handle 1:1 ratio where the plasma machine does not have a voltage reducer. That is model THCAD-300. As soon as I get back to my computer I will post links to these items in the Mesa store. You can indeed use either a 7i96 or 7i96S - combined together with a THCAD-300 - and not need a high voltage resistor. The only downside there is that you will have high voltage on a wire coming from the plasma machine to the THC module. You can do as I did by moving the THC module out of the control box and placing it on the plasma machine to minimize how far that high-voltage is traveling outside of a control box. Because I moved my THC module over to the plasma machine, really the only thing I gained by using the HV resistor was not having to send back my THC module to buy another one. I selected and bought my THC module before I bought my plasma machine. Then when I bought my plasma machine, I was shopping all kinds of features versus price and lost track of paying attention to its voltage ratio, and wound up getting a mismatch where my plasma machine is a 1:1 ratio without a voltage divider or reducer. LINKS to MESA store for the items mentioned: MESA 7i96 - no longer listed for sale, use 7i96S instead. MESA 7i96S - store.mesanet.com/index.php?route=product/product&product_id=374&search=7i96 MESA THCAD-2 - store.mesanet.com/index.php?route=product/product&product_id=365&search=thcad MESA THCAD-5 - store.mesanet.com/index.php?route=product/product&product_id=328&search=thcad MESA THCAD-10 - store.mesanet.com/index.php?route=product/product&product_id=127&search=thcad MESA THCAD-300 - store.mesanet.com/index.php?route=product/product&product_id=128&search=thcad store.mesanet.com/index.php?route=product/product&product_id=128&search=thcad Shop all MESA THC options: store.mesanet.com/index.php?route=product/search&search=thcad
Thanks for the series Doug! I'm about to pull the trigger on a LR2 to LR3 upgrade kit from V1 so I can build a CNC plasma with my father in law, but I'm curious: What's the purpose of the separate control box vs. just using something like the SKR Pro? Is the integrated board not heavy duty enough? Doesn't have ability to control the torch? Etc.? Thanks for any help here!
The key reason is for Automatic Torch Height Control, so that when heat from cutting makes the metal warp and bend your system can adjust as needed on the fly. The hardware and software needs to be designed for plasma to handle this. See my most recent video for more about all this!
Doug I didn't see a link in description to Mesa THCAD2. Can you give us a bit more info on this board. I am curious if the board can control a stepper motor on it's own or if it requires the 7I96S. I also am interested if there is a Mesa board that works with the 1 to 1 volts from plasma cutter, sounded like Mesa may have one and wouldn't need to add resistor. Thanks
The Mesa board that I show inside the control box, 7i96S, is the one that controls the stepper motors. The only thing the Mesa THCAD-2 does is monitor & control the torch height. Mesa does indeed sell a torch height control board that can handle 1:1 ratio where the plasma machine does not have a voltage reducer. That is model THCAD-300. As soon as I get back to my computer I will post links to these items in the Mesa store.
You can indeed use either a 7i96 or 7i96S - combined together with a THCAD-300 - and not need a high voltage resistor. The only downside there is that you will have high voltage on a wire coming from the plasma machine to the THC module. You can do as I did by moving the THC module out of the control box and placing it on the plasma machine to minimize how far that high-voltage is traveling outside of a control box.
Because I moved my THC module over to the plasma machine, really the only thing I gained by using the HV resistor was not having to send back my THC module to buy another one. I selected and bought my THC module before I bought my plasma machine. Then when I bought my plasma machine, I was shopping all kinds of features versus price and lost track of paying attention to its voltage ratio, and wound up getting a mismatch where my plasma machine is a 1:1 ratio without a voltage divider or reducer.
@@design8studio Thanks for all the feedback. I am looking to see if this THC can work with my Arduino setup on plasma cutter. I will dive deeper in to see what I can find.
@@digitizer101 I've combined the answers given with a video of me assembling and mounting my printed case for the THCAD2, which I am about to post any minute now! 🙂
It appears to me you have left something out in this build,, that will be critical for a plasma machine. The presence of EMI will be a real problem without shielded cables and a path for shielding to ground.
The build I did works fine, so whatever I may have left out, seems to not be critical (which would imply "cannot work without it"). Re. shielding to ground: My grounded metal case (around the electronics boards) may be providing protection that helps make my setup work. I grant that perhaps in some other situations, additional steps might be needed.
I'm just saying anyone using this as a blueprint for their project should be aware that plasma cutter and VFD are known to emit EMI, or harmonics that can cause problems so shielded cables are highly recommended. 😊
LINKS to MESA store (for the items mentioned) are below in this comment!
Kudos and many thanks to both Ryan, the founder of V1 Engineering (@vicious1 on the V1E forum), and Kyle (@kd2018 on V1E forum) for their invaluable help. In fact, both Ryan and I used, as guidance, Kyle's immensely helpful plasma build thread which includes many tutorial type posts including both wiring schematic and LinuxCNC software setup info and help.
In response to questions in comments about the links for the MESA items, and whether or not a MESA card is available for 1:1 ratio where the plasma machine has no voltage divider, see below. Also regarding questions of whether or not MESA makes a card that does both control of steppers and THC (torch height control), to my knowledge two cards are required, one for each. Kyle used MESA 7i96 for stepper control and MESA THCAD-10 for torch height control. My setup is similar, but I am using MESA 7i96S and MESA THCAD-2. All these setups also require some device (usually a used laptop) running LinuxCNC. A touchscreen type laptop is helpful, but not a necessity.
MESA previously sold one THC A-to-D card for 1:1 ratio (THCAD-300), and two for divided (reduced ratio), a 5v option (THCAD-5) and 10v option (THCAD-10). The new THCAD-2 is able to emulate either a THCAD-5 (5v option) or a THCAD-10 (10v option) based on a jumper setting! So its ability to go either way seems to be the reasoning behind the "2" in its name.
WHICH RESISTER IS THAT? SEE HERE:
Finally, if you have a plasma machine with 1:1 ratio (no voltage divider) and you should find yourself wanting to reduce the voltage yourself in order to use a THCAD other than 300, either 5v, 10v, or a "2" acting as a 5v or a 10v, then per Peter, the founder of MESA (to me via email when I bought a THCAD-2 instead of THCAD-300):
"You could return the THCAD2 card for credit and re-order a THCAD-300. Another option would be to add an external resistor to the THCAD2 in the negative lead, say 2.4M for 250V full scale. For safety this should be a HV resistor like: www.digikey.com/en/products/detail/vishay-beyschlag-draloric-bc-components/HVR3700002404FR500/719541
The 250 range improves the resolution somewhat (and continuous overvoltages up to 1000V are no problem)."
The following are copied and pasted from my replies in comments, placed here so I can pin this to the top. Happy making!
The Mesa board that I show inside the control box, 7i96S, is the one that controls the stepper motors. The only thing the Mesa THCAD-2 does is monitor & control the torch height. Mesa does indeed sell a torch height control board that can handle 1:1 ratio where the plasma machine does not have a voltage reducer. That is model THCAD-300. As soon as I get back to my computer I will post links to these items in the Mesa store.
You can indeed use either a 7i96 or 7i96S - combined together with a THCAD-300 - and not need a high voltage resistor. The only downside there is that you will have high voltage on a wire coming from the plasma machine to the THC module. You can do as I did by moving the THC module out of the control box and placing it on the plasma machine to minimize how far that high-voltage is traveling outside of a control box.
Because I moved my THC module over to the plasma machine, really the only thing I gained by using the HV resistor was not having to send back my THC module to buy another one. I selected and bought my THC module before I bought my plasma machine. Then when I bought my plasma machine, I was shopping all kinds of features versus price and lost track of paying attention to its voltage ratio, and wound up getting a mismatch where my plasma machine is a 1:1 ratio without a voltage divider or reducer.
LINKS to MESA store for the items mentioned:
MESA 7i96 - no longer listed for sale, use 7i96S instead.
MESA 7i96S - store.mesanet.com/index.php?route=product/product&product_id=374&search=7i96
MESA THCAD-2 - store.mesanet.com/index.php?route=product/product&product_id=365&search=thcad
MESA THCAD-5 - store.mesanet.com/index.php?route=product/product&product_id=328&search=thcad
MESA THCAD-10 - store.mesanet.com/index.php?route=product/product&product_id=127&search=thcad
MESA THCAD-300 - store.mesanet.com/index.php?route=product/product&product_id=128&search=thcad
store.mesanet.com/index.php?route=product/product&product_id=128&search=thcad
Shop all MESA THC options: store.mesanet.com/index.php?route=product/search&search=thcad
Awesome design. Thanks for sharing 👍
Thanks for the series Doug! I'm about to pull the trigger on a LR2 to LR3 upgrade kit from V1 so I can build a CNC plasma with my father in law, but I'm curious: What's the purpose of the separate control box vs. just using something like the SKR Pro? Is the integrated board not heavy duty enough? Doesn't have ability to control the torch? Etc.? Thanks for any help here!
The key reason is for Automatic Torch Height Control, so that when heat from cutting makes the metal warp and bend your system can adjust as needed on the fly. The hardware and software needs to be designed for plasma to handle this. See my most recent video for more about all this!
@@design8studio Ah! Thank you very much! I’ll send some affiliate link clicks your way!
@@AndrewReuter Happy to help!
Doug I didn't see a link in description to Mesa THCAD2. Can you give us a bit more info on this board. I am curious if the board can control a stepper motor on it's own or if it requires the 7I96S. I also am interested if there is a Mesa board that works with the 1 to 1 volts from plasma cutter, sounded like Mesa may have one and wouldn't need to add resistor. Thanks
The Mesa board that I show inside the control box, 7i96S, is the one that controls the stepper motors. The only thing the Mesa THCAD-2 does is monitor & control the torch height. Mesa does indeed sell a torch height control board that can handle 1:1 ratio where the plasma machine does not have a voltage reducer. That is model THCAD-300. As soon as I get back to my computer I will post links to these items in the Mesa store.
You can indeed use either a 7i96 or 7i96S - combined together with a THCAD-300 - and not need a high voltage resistor. The only downside there is that you will have high voltage on a wire coming from the plasma machine to the THC module. You can do as I did by moving the THC module out of the control box and placing it on the plasma machine to minimize how far that high-voltage is traveling outside of a control box.
Because I moved my THC module over to the plasma machine, really the only thing I gained by using the HV resistor was not having to send back my THC module to buy another one. I selected and bought my THC module before I bought my plasma machine. Then when I bought my plasma machine, I was shopping all kinds of features versus price and lost track of paying attention to its voltage ratio, and wound up getting a mismatch where my plasma machine is a 1:1 ratio without a voltage divider or reducer.
@@design8studio Thanks for all the feedback. I am looking to see if this THC can work with my Arduino setup on plasma cutter. I will dive deeper in to see what I can find.
@@digitizer101 I've combined the answers given with a video of me assembling and mounting my printed case for the THCAD2, which I am about to post any minute now! 🙂
It appears to me you have left something out in this build,, that will be critical for a plasma machine. The presence of EMI will be a real problem without shielded cables and a path for shielding to ground.
The build I did works fine, so whatever I may have left out, seems to not be critical (which would imply "cannot work without it"). Re. shielding to ground: My grounded metal case (around the electronics boards) may be providing protection that helps make my setup work. I grant that perhaps in some other situations, additional steps might be needed.
I'm just saying anyone using this as a blueprint for their project should be aware that plasma cutter and VFD are known to emit EMI, or harmonics that can cause problems so shielded cables are highly recommended. 😊