Development Environment

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Development Environment

If you follow the GitHub repository https://github.com/ThingEngineer/ReactorForge by clicking [Watch] you may have noticed work on the firmware. I’ve begun setting up the new development environment. Going forward, I don’t want to deal with switching to Windows to work in AVR Studio. I never liked that environment anyway. I had talked about possibly moving everything into the Arduino environment because of its popularity, however that has its own set of issues. For starters, support for the AT90PWM family of chips isn’t there, and I don’t want to spend the time to add it. Then there’s this:

https://atom.io + https://atom.io/packages/platomformio = frickin awesome

Beginning Development Environment

Arduino is a great prototyping platform and IDE to get started on if you have never worked with microcontrollers. As a beginner, it can get you building projects faster than any other platform out there. But eventually, the features that make it convenient and easy to use can hold you back. It lacks many features which make writing code quicker, easier, and have become quite standard in modern text editors. There are also bits of code that get inserted into your code that can cause some very head-scratching issues.

Moving Beyond Arduino

The next logical step is to leave the Arduino IDE behind. We do that by working in a more fully-featured development environment. Atom + PlatformIO is my new favorite open source cross-platform IDE. It even comes with the Arduino framework among others. That lets you test drive it with a code structure you are familiar. When you are ready, you can remove the training wheels and go full native C++. There is so much more I could brag about with both of these tools. But I’ll let you discover the awesomeness yourself!

Development Environment

Next Steps

What’s next? I’m going to begin porting over the libraries used in the existing project. Then the main code, and start rewriting, optimizing, etc. The photo above is a test rig I used for setting up the new IDE. I will continue to use it throughout the porting process. Once the code is stable in its new environment, I’ll switch over to the ReactorForge!

I had also planned on using this setup to demo and explain the basics behind the AT90PMW software PLL setup. I’ll get to that but for now, it’s back to work in the new development environment!

Mains Power Feed Complete

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Mains Power

This is the last mains power update for the ReactorForge Induction Heater. It will be the last because it’s complete! Here is how the last couple days of that process went.

Mains Power

I started by connecting the jumpers from the custom splice connector to the 60 Amp 240-volt dual pole breaker and ground bus. The photo shows green hooked to the neutral bus. I later moved this as I did not need to tap 120-volt like I thought I would have to since the ATX power supply runs on 240-volt now. (I just forgot, it’s been a while.)

Mains Power

And here is the 240-volt quick disconnect assembly installed and ready. I will print another version of the slide lock. The slides should be solid so the splice connectors are not accessible while the wires are disconnected.

Mains Power

Next, I prepared the 2 AWG mains power feeder lines. These will connect the splice block directly to the input of the ReactorForge.

Mains PowerMains Power

The splice block side has thick metal tabs that are double layered with heat-shrink tubing. These provide a high current, high durability connection to the screw terminal that will stand up to multiple connect/disconnect cycles.

Mains Power

The Induction Heater side has heavy duty lugs that will accept the terminal post. These are also insulated with double layers heat-shrink.

Mains Power

Bringing It All Together

And here you can see the feeder lines connected to the input of terminal posts on the back of the ReactorForge. I also ran a USB extension with a small hub for connecting the Atmel ISP programmer. I put the Bluetooth dongle here as well. It communicates with the mainboard to send/receive commands and system telemetry.

Mains PowerMains Power

I then installed a variac between the mains contactor and the inverter input filter.

Mains Power Variac

When software activates the contactor, 240 volts directly feeds the inverter typically. Since I have a decent amount of testing to do, I severed that connection and installed the variac to allow lower power testing.

Mains Power

I taped up the small areas where 240 volts was accessible in the front to avoid accidental contact or tools shorting things out. Getting my fingers across 240-volt mains power is not something I want to experience twice!

Mains Power VariacMains Power

On To The CODE!

That’s it for cooling and mains power connections. The next step is to get the programming environment set back up. I will turn things up as is and do some testing to make sure everything is still good. Once that is done I will get right to the next big task, I’ve decided to port the entire thing to Arduino. This won’t be too difficult since the code is already in C and I will be glad to get away from AVR Studio, to be honest. I made the choice to move to Arduino due to is massive use and rise in popularity over the last few years. Since this is an open source project I want to use a platform that people are familiar with. Let’s put industrial level induction heaters right up there with open source 3D printer firmware!

ReactorForge History – A brief history lesson 01010010

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ReactorForge History

There were many before it, after it and in-betweens, but these are the milestones! This is a brief ReactorForge History lesson.

ReactorForge History

From left to right.

  • The first MOSFET version on a PCB. It worked great but didn’t couldn’t handle the power level I wanted. I ended up pushing it to failure and moving to brick IGBTs.
  • The first IGBT version on a PCB. This design is based on a CD4046 PLL and uses gate drive transformer to drive the large brick IGBTs (the ReactorForge now uses hybrid drivers). If you are into electronics and you’ve never worked with a PLL, even if just on a breadboard you should. PLL’s are very well documented, fascinating little devices. This circuit works great but its frequency operation range was limited by the external passives for the VCO (voltage controlled oscillator). Due to its reliance on these passive components, it is also affected by temperature.
  • For mainly that and a few other reasons I decided to explore a software PLL solution. After going around the usual suspects and understanding how a PLL worked I thought there must be some way to do it with a low-cost MCU, not a freaking FPGA or high power processor. Maybe some type of PWM/comparator combination I thought. I found my solution in a motor controller, or power stage controller chip made by Atmel, the PSC216,316 microcontroller. That’s what this breadboard is, the early testing for what is now a rock-solid way to find the resonant frequency (Fr) and adjust power levels by offsetting that frequency from the current Fr all while soft switching (i.e. not making heat in the wrong places and exploding electronics). This was the result of those early tests…

ReactorForge History - Current

The Future:

One more board redesign may be in order but we’ll see. I may look into reducing the size of the board down the standard Eurocard PCB size of 100mm x 160mm. Although the current size is still within the free size limit of 160mm^2 for Autodesk Eagle.

That was the ReactorForge History, now let’s forge ahead to the future!