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Forum Index : Electronics : Nano control board pre run instructions
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| BenandAmber Guru  Joined: 16/02/2019 Location: United StatesPosts: 961 |
This post will be advice for what to do after you've installed the components on your new Nano control board Everyone and anyone feel free to leave some advice Poida the Great wrote How to bring up the nanoverter: First, prove 15V, 12V and 5V, at the DC-Dc converter output, 7812 and 7805 outputs when you feed the DC-DC converter 48V or something like it. While powered up, check there is 15V on pin 7 of the IR21844, and 5V on the 2 nano's supply pins, pin 27 remove power. Don't forget to use pin sockets for both nanos, both IR21844 and both LT1638 Then program both nanos, label them "1" and "2" and install. Maybe it's better or even that it works at all, to program them whilst removed from the board. I had issues when programming one nano today, but I think it was a dodgy item. Bad things happen when you put nano1 into socket 2 or nano2 into socket 1. I did this and blew stuff up. Make up a push button momentary ON switch, to plug into J12. Again, apply power to DC-DC converter, and then when you push the switch, you should see the Green LED D3 light up. press it again and after a couple of seconds or less, it dims. This is when it's handy to have an oscilloscope: press the switch again, D3 lights up and probe for PWM on pin 1 of both the IR21844 sockets. You should be able to see the PWM change as the soft start runs up to maximum duty cycle, to stay there. And then when you press the button again - to stop the inverter - you will see the PWM reduce over 3 seconds, eventually to nothing. Once you see this, then we need to check the correct operation of the IR21844 shutdown pins. These need to be zero volts when not running, even before, during and after you apply power to the dc-dc converter. Then we need to see it go to 5V when you start the inverter by pressing the button. There should be 5V present on pin 2 of both IR21844 sockets whenever the green LED D3 is lit up. After all this, then it's time to install the IR21844 ICS, the two op amps, and provide the 12V AC feedback on J7. We need to turn the VFB adjuster R31 clockwise all the way until you can hear and feel it click, click.. This puts the VFB setting to the lowest output voltage, hopefully much lower than what you will eventually set it to. Remove power. What a little to make sure nothing is on any of the 10 pins of the connector. Connect the 10 pin ribbon to the power board, run the inverter with power supplied to the inverter power board. If all is well, you could then adjust R31 to the required AC output. I would not build the power board with all MOSFETS installed. I would only build it with 1 for each of the 4 legs of the bridge. And I would install a small capacitor, if any, in the DC supply locations. This is the power board I would first try things with, to prove the correct operation of the nanoverter control board as well as the power board. No load testing is needed nor would it be helpful at this stage. And no heat sinks are required when testing it with zero loads. Then once things are going well, add all the MOSFETS, all the DC bulk caps and test it. With the addition of the huge DC bulk caps, any issues will result in a bit of fireworks and the need to replace large numbers of FETS. Oh, and when soldering the FETS, I leave a bit of length on the leads, enough to let me get the side cutters easily onto the leads should I have to replace them. It's best to snip all 3 leads first, then de-solder the short remaining lead bits, rather than try to de-solder the entire MOSFET, 3 leads at once. RenewableMark and I have both found that there is a big difference in 7812 and 7805 regulators, depending on who made them and country of origin. Mark found one reg was getting stupidly hot and not functioning, leading to shutdowns etc. When running, both regulators should be near room temperature. Also, be aware that connecting the laptop to nano2 and opening the Arduino terminal will usually cause nano2 to reboot. This takes a few seconds before it can respond. The LCD shows whats happening. I like using a laptop to do this comms since it is isolated from ground. Mark has found that using a PC, while that PC was powered by the running inverter can give poor results when setting the calibration values. Ground loops probably. When I am setting the calibration values or the temperature settings, I only connect to nano2 when the inverter is not running. Then once the terminal is up and I have the menu (press ? to get it) I start the inverter. be warned i am good parrot but Dumber than a box of rocks |
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poida Guru Joined: 02/02/2017 Location: AustraliaPosts: 1418 |
And since there can be ground loop issues, that upset calibration, if you have an Android based phone, you can do this:  Use the phone as a terminal. This is isolated and so it is ideal for accurate calibration. Just get a $4 USB OTG cable to suit the phone. My Samsung Galaxy S7 needed a micro USB type. The terminal app is free. It works really well. wronger than a phone book full of wrong phone numbers |
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| BenandAmber Guru Joined: 16/02/2019 Location: United StatesPosts: 961 |
Is there anything special about that cable or is it just pin-to-pin big to little conversion I am ready to take a stab at programming hopefully I can get it right without questioning everybody to death be warned i am good parrot but Dumber than a box of rocks |
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| poida Guru Joined: 02/02/2017 Location: AustraliaPosts: 1418 |
It is not pin for pin, I tried that and wasted hours. It's just a little bit special, using pin 4 (mode select or ID) in a way I do not know. They are cheap to buy and I should have just bought it first. wronger than a phone book full of wrong phone numbers |
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| BenandAmber Guru Joined: 16/02/2019 Location: United StatesPosts: 961 |
Once again your are awesome poida the great I will be attempting to load my two Nanos here very soon Is there a special link to the latest code for use with Android phone be warned i am good parrot but Dumber than a box of rocks |
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| BenandAmber Guru Joined: 16/02/2019 Location: United StatesPosts: 961 |
POIDA THE GREAT wrote to program the nanos, it's best to use a PC or laptop. download the Arduino programming software, install it. Then you need to add a special extra library to the Arduino programmer software. The library is called "LiquidCrystal_PCF8574" To install this, (once the Arduino program is running..) go to Tools, then Manage Libraries, then in the right of 3 text boxes type LiquidCrystal_PCF8574 hover over the result, and "select version" appears, chose what version is available and install it. Now you can compile the programs for both nano1 and nano2. You will need a driver for the cheap Chinese Nanos that come with the CH340x serial to USB chips. The genuine and more expensive Nanos use FTD232 serial to USB chips and the Arduino software comes with drivers already. The windows driver for CH340x is found (as well as other locations) at https://sparks.gogo.co.nz/ch340.html For any lunatic Mac users, of which I proudly include myself, the CH340x drivers are at https://github.com/adrianmihalko/ch340g-ch34g-ch34x-mac-os-x-driver and use version 1.5 Some nanos come with the current bootloader, others come with the old bootloader. They are not compatible! Not the same. but we can use either nanos anyway. Just choose, from the Arduino software, "tools", then "processor" either "ATMega328P" or "ATMega328P (old bootloader)" You can break anything if you choose the wrong one. You have to find out which bootloader you have for each of the nanos by trying one of the other methods. Of course, before compiling or uploading the codes, you must choose the correct board. (go to "Tools", then "board" and choose "Arduino Nano") It works reliably on both the Windows 7 PC I use at work and the Mac laptops and iMac I use at home. Thanks for all your valuable time poida the great !!! Now, to answer another question: No, I do not reccommend you use the Android phone to program the nanos. I have read poor reviews of the Android Arduino programmer software. But, by all means use the terminal program and a USB On The Go cable to configure already programmed nanos. I do this and it works perfectly. be warned i am good parrot but Dumber than a box of rocks |
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| poida Guru Joined: 02/02/2017 Location: AustraliaPosts: 1418 |
When using the Android mobile phone and cable to connect, one thing to keep in mind is to ensure the terminal app is using the same baud rate as the nano expects. Ensure the comms settings are 115200, 8 bits, no parity and 1 stop bit. I use the app "Serial USB Terminal", by Kai Morich probable stale link wronger than a phone book full of wrong phone numbers |
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