Introduction to CAN bus for your 3D Printer - (Voron) CANBUS

if you've spent time in a 3D printing Community lately you've probably heard people talking about can bus and wondered what the heck is canvas this video is an introduction to can bus and I hope it helps make sense of it all this isn't a how-to video there are other resources for that which we'll share this is an explanation of the what and how of can so you can make the right choices for your printer real quickly can stands for controller area network and was developed by Bosch electronics for use in vehicles its main purposes are to eliminate wiring and create electronic subsystems that can talk to each other so what does this mean for your printer well Clipper supports multiple controller boards and a can tool headboard is a controller board that's small enough to mount on your printer's tool head instead of running a traditional wiring harness to the tool head we only have to run four wires the plus v minus can high and can low if you consider a full-sized voron with a stealth burner there are a lot of wires going through the cable chains to the tool head two for the hot end two for the thermistor two for the part cooling fan two for the hot end fan three for the probe three for the LEDs and four for the extruder motor if we install a can bus tool head which has its own Electronics we can run everything with four wires because we're just sending power in digital Communications between the tool head and the computer running clipper since there are only four wires you can convert from cable chains to an umbilical harness if you want removing the cable chains removes mass and drag from the Gantry and that may result in better acceleration another benefit is that by using the controllers in the tool headboard you free up resources on your main controller for example if you have a v0 with a small main controller and you add a can tool head you now have spare fan controllers and stepper drivers on your main board this makes it easy to control a never more or even add more LEDs to make your printer go faster because LEDs make your printer go faster there are a lot of options to consider when installing a can system so let's run through what you need to think about the first thing is picking the right board this generally comes down to size and there are a couple of variations boards with 36 in the name like the ebb 36 are designed to mount behind a round Nema 14 extruder motor boards with 42 in the name like the ebb42 are designed to mount behind a square Nema 17 motor or be used with third-party extruders there's also now a board built like heart case two-piece stealth burner PCB the next decision is how you're going to connect to the can board the more traditional way is to use a USB to can adapter like the u2c this connects to your Raspberry Pi over USB then can to the tool head with a power pass-through a newer option is to use can bridge mode with supported controllers like the octopus and octopus Plus you flash a new version of firmware into the octopus then connect the can port on the board to the tool headboard well a lot of people are doing this successfully there are also a lot of people that have had problems so be prepared for some troubleshooting if you want to go down this road now let's consider the wiring path you can run your can wires through the existing cable chains but if you want to get less repetitive bending on your harness and shorten the cables you would go umbilical then you can remove the X and Y axis cable chains which brings us to the next choice which is end stops if you're leaving the cable chains you can use the X Y and stop board and cables if you're switching to an umbilical harness you can move the end stop switches I have my X stop on the tool head carriage and the Y stop on the a motor mount for example or you can go with sensorless homing and have no wires at all next take a look to see if you have enough length on your tool head component wires to reach where the can board will go is there enough slack for your fans heater and thermistor to reach or do you need to replace the parts or extend the wires better to figure it out now determine how long your new can harness needs to be it's always better to overspec you can trim the wires later you can use 24 gauge for the can signals the power wires will depend on how much amperage you think you'll need at the tool head A good rule of thumb is 20 gauge if you use a standard flow hot end or 18 gauge for high flow once you've made your choices you'll need to get your boards and wires as well as find or design any parts you need to move your end stops or connect an umbilical system get everything printed and test fitted if you can goes without saying that you don't want to find out you need to print a part after you rip apart your only printer so now that you have everything gathered it's time to get to work first always read the instructions on the can board there will be plenty of information in there to help you figure out what you need to do remove the old wiring and any parts you're not going to use Mount the can board terminate your tool head components and pay special attention to the extruder motor wiring if you have a multimeter always test for resistance between your wires to figure out what the pairs are take your can signal wires and twist them so they have about one turn per inch you don't have to do this with the power wires just the can high and low this helps them reject electrical noise then run the cables from the electronics Bay to the tool head make sure you enable the 120 ohm termination at both ends of the chain for example if you're using a u2c and an ebb36 you want to put a jumper on the 120 terminal on each board this is important for the can bus to work reliably and with the hardware done now it's time for software first read the instructions for your can board this should give you all the information you need to configure your setup you may need to install a bootloader think of your can board as a computer that hasn't been set up yet first we have to load the operating system and then we can load the program which is clipper this isn't a technically correct analogy but it's a reasonable one some boards are starting to ship with the bootloader pre-installed so you would just have to install the firmware but again check the documentation to be sure you'll usually have to install the bootloader by connecting the board to your Raspberry Pi with a USB cable if your board is compatible it's recommended to install can boot because that allows you to flash the firmware over the can connection later on without can boot you'll have to connect your board to the pi with USB if you need to update the tool head firmware once the bootloader is installed it's firmware time use a terminal program to connect to the Raspberry Pi and make the firmware from the make menu follow the manufacturer's settings but check the connection speed s lower than 500k have been causing problems so I'd consider 500k to be the minimum don't even think about 250k if you want to be on the safe side I'd go up to 1000k after you build the firmware file you'll flash it to the board next you need to create the can connection settings on the Raspberry Pi itself this is done through terminal again the instructions should have the settings that you need but make sure you set the bus speed to match whatever speed you set in the firmware or the can connection won't work if everything has worked to this point the final step is to update your printer.cfg file to use the new board you'll add a new MCU entry which will include the uuid of the can bus board then you have to change the pin assignments for everything plugged into the can board that's the heater thermistor fans probe the xn stop if you moved it to the carriage your LED pin and the extruder stepper don't forget to define the uart pin it's separate from the extruder section and is easy to miss then your extruder motor draws too much current and melts into the extruder and you have to replace a bunch of parts not that I know this from experience and now it's time to test everything like it's a new build check that your end stops work in Mainsail or fluid before you try and move anything if they work do a home and keep your hand on the emergency stop if you've moved the end stops you may need to update your configuration due to the new Switch positions things like your Z end stop switch probe docking Auto Z calibration and nozzle scrubbing next make sure everything on the tool head works check your part cooling fan and turn the heater to 50 degrees to make sure the hot end works and the hot end fan comes on Buzz your extruder to make sure the motor is working correctly and before you try to print do an extrusion test to make sure that the motor is turning in the right direction the new stepper driver may need to be inverted and make sure your logo LED is doing its thing once you're sure everything's working as you expect you should probably run your input shaping again you've added Mass to the tool head with the can bus board and you might have lost some mass on your Gantry so a retune is an order and with that we've come to the end of our journey you should Now understand what can is and what it will do for you and the basics of how to convert your printer or build your printer using a can bus tool head if you'd like to buy can bus boards or just about any other part you need for your printer visit west3d.com where you'll be able to find what you need

Channel: West3D Printing

Views: 68,971

Keywords: CAN, Voron, CANBus, Introduction, What is CAN, Voron Mod

Id: mwpI7dCOgh0

Length: 10min 39sec (639 seconds)

Published: Fri Sep 30 2022