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BigTreeTech Can Bus with Voron Revo

pfm

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I'm doing the Can Bus mod on my Trident. BigTreeTech has a kit specifically designed for Stealthburner. It uses some super-tiny JST connectors on the toolhead board that require me to re-terminate several wires. I'm running the Revo Voron hot end. The thermistor wires are insulated with a cloth insulation which is far too fat to go into the jacket portion of the tiny JST terminal crimp end. A simple solution it to solder some pre-crimped leads onto the ends of the thermistor wires. BigTreeTech includes a set of pre crimped leads in the kit. They are not marked and the BTT manual does not mention them, but presumable, these are leads that can be soldered to wires ends rather than crimping the JST terminals on. As far as I can tell, theses leads are 26AWG (and they are solid wires). I'm having trouble determining the size of the leads on the Revo thermistor (and E3D does not specify). But, I'm thinking they might be 24 AWG stranded. Here's my question -- does anyone know what ampacity I need for the Revo thermistor? Or maybe a better way to say it is, how much current is flowing through the thermistor wires at my over-temp threshold (300C). If I solder the leads provided by BTT in the kit onto the Revo Thermistor wires, Is 26AWG sufficient to carry the current?
 
I'm doing the Can Bus mod on my Trident. BigTreeTech has a kit specifically designed for Stealthburner. It uses some super-tiny JST connectors on the toolhead board that require me to re-terminate several wires. I'm running the Revo Voron hot end. The thermistor wires are insulated with a cloth insulation which is far too fat to go into the jacket portion of the tiny JST terminal crimp end. A simple solution it to solder some pre-crimped leads onto the ends of the thermistor wires. BigTreeTech includes a set of pre crimped leads in the kit. They are not marked and the BTT manual does not mention them, but presumable, these are leads that can be soldered to wires ends rather than crimping the JST terminals on. As far as I can tell, theses leads are 26AWG (and they are solid wires). I'm having trouble determining the size of the leads on the Revo thermistor (and E3D does not specify). But, I'm thinking they might be 24 AWG stranded. Here's my question -- does anyone know what ampacity I need for the Revo thermistor? Or maybe a better way to say it is, how much current is flowing through the thermistor wires at my over-temp threshold (300C). If I solder the leads provided by BTT in the kit onto the Revo Thermistor wires, Is 26AWG sufficient to carry the current?
Here's a bit more info. The Revo uses the Semitec 104NT-4-R025H42G Thermistor. According to Semitec, the resistance at 300C is 8.28 Ohms. So at 24V, that's 2.9 Amps. The max current for 26AWG wire is 2.2 Amps continuous. So it's no go. At 280C the resistance is 11 Ohms drawing 2.18 Amps. So, I could limit my hotend to 275-280C. 24AWG is rated for 3.5Amps --that's a much more comfortable number. Having said all of this -- I'm still a bit unsure what size these jumpers are. Note to BTT -- LABEL YOUR PARTS. Its super frustrating to get mystery parts in a bag. I'll try sending BTT an email and see if they respond.
 
Hi, thermistor wires you can either try to do this like on image below https://docs.vorondesign.com/build/electrical/#microfit-pins or just solder JST-GH pigtail provided by BTT. It will work for this distance, additional solder joint and thinner wire on those few cm should not cause very different readings to not be usable. I do not think we are feeding full >2A through thermistor wire.

And yes, BTT had been screamed at for using these shitty connectors rated for AWG 26 wire 😩
 
Can I ask a slightly different question? I have a Revo extruder on my Voron 2.4. I am looking at the BTT SB2240 and the Mellow SB2040 toolhead boards to implement CanBus.

Both these boards say they work with PT100 and PT1000 thermistors but I cant find any information whether they will work with Revo thermistor. I have currently got the thermistor Mainsail configured in Mainsail as generic 3950.

I presume Revo works with these CanBus boards but I want to confirm it before I splash out and order one.

Thanks

Peter
 
Can I ask a slightly different question? I have a Revo extruder on my Voron 2.4. I am looking at the BTT SB2240 and the Mellow SB2040 toolhead boards to implement CanBus.

Both these boards say they work with PT100 and PT1000 thermistors but I cant find any information whether they will work with Revo thermistor. I have currently got the thermistor Mainsail configured in Mainsail as generic 3950.

I presume Revo works with these CanBus boards but I want to confirm it before I splash out and order one.

Thanks

Peter
I can't comment on the Mellow, but the BTT SB2240 definitely supports the Revo thermistor. It's a different connector from the PT100 connector.
 
Can I ask a slightly different question? I have a Revo extruder on my Voron 2.4. I am looking at the BTT SB2240 and the Mellow SB2040 toolhead boards to implement CanBus.

Both these boards say they work with PT100 and PT1000 thermistors but I cant find any information whether they will work with Revo thermistor. I have currently got the thermistor Mainsail configured in Mainsail as generic 3950.

I presume Revo works with these CanBus boards but I want to confirm it before I splash out and order one.

Thanks

Peter
Hi, you probably mean E3D Revo hotend, not extruder? This one https://e3d-online.com/products/revo-voron ? What toolhead do you use? Standard Stealthburner?
Revo hotend has thermistor built into the ceramic heater. You cannot change it for PT1000 or any other. Standard thermistor with Revo is 104NT-4-R025H42G so if you have it defined in printer.cfg as Beta3950 that's wrong and you should correct it.

You will have to take a look whether the board you buy has MAX31865 chip if you want to use PT100. PT1000, 104NT and NTC100k will work without it. Word of advice: if you do not enjoy crimping super-super tiny JST-GH terminals, do not buy those boards from BTT.
 
It uses some super-tiny JST connectors on the toolhead board that require me to re-terminate several wires. I'm running the Revo Voron hot end.
Not your question, but these are the connectors. Pre-terminated for 100% simpler assembly:


JST PicoBlade 1.25mm

BTT also has a new version with PH2.0 connectors.
 
I have already broken my head and can not understand anything with this ATC Semitec 104NT-4-R025H42G. Can someone throw a picture or a diagram of how exactly it should be connected to the 2240 and what should be specified in the config? all over the internet only some fragments of information, I as a beginner can not put it all together in a pile and get a working solution. "shutdown: Thermocouple reader fault" I decided to build a second print head on this "Voron compatible" Hotend, and it doesn't seem to be compatible at all. I'd rather buy a regular Phaetus with a normal PT1000.
 

Attachments

  • [mcu EBBCan2].txt
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BTT's github is the best source for information.


Confusingly, they have two EBB2040s. One is EBB SB2240_2209 The other is EBB2209 (RP2040). The newer one - (RP2040) - has larger connectors - the ones that are "standard" for most printer electronics.

If you are using a 104NT, then just connect it to the TH0 pins. Thermistors are not polarized. (Ignore the 4 pin Max13864 header right next to it). You only really need to use a Max13864 type thermistor if you are doing really high temp stuff like PA6 or PEEK, etc. Those need a higher temp range thermistor than a "common" 104nt.

For both 2040s, the TH0 pins are in about the same place. Just different connectors. Two pin headers at the bottom edge close to the front.

Pinouts (link to github page image:
RP2040
SB2240

SB2240 Config is as follows for the extruder:

Code:
[extruder]
step_pin: EBBCan: PD0
dir_pin: !EBBCan: PD1
enable_pin: !EBBCan: PD2
microsteps: 16
rotation_distance: 33.500
nozzle_diameter: 0.400
filament_diameter: 1.750
heater_pin: EBBCan: PB13
sensor_type: ATC Semitec 104NT-4-R025H42G
sensor_pin: EBBCan: PA3
control: pid
pid_Kp: 21.527
pid_Ki: 1.063
pid_Kd: 108.982
min_temp: 0
max_temp: 300

RP2240 cfg code:

Code:
[extruder]
step_pin: EBBCan:gpio18
dir_pin: !EBBCan:gpio19
enable_pin: !EBBCan:gpio17
microsteps: 16
rotation_distance: 33.500
nozzle_diameter: 0.400
filament_diameter: 1.750
heater_pin: EBBCan:gpio7
sensor_type: ATC Semitec 104NT-4-R025H42G
sensor_pin: EBBCan:gpio27
control: pid
pid_Kp: 21.527
pid_Ki: 1.063
pid_Kd: 108.982
min_temp: 0
max_temp: 300

(edit - I was wrong about the same CFG for both 2240 boards. now fixed)

Reference link for different types of thermistors:


(also a great resource to figure out the settings when doing this your first time.)

I edited the default config to include the correct thermistor reference for you.

The "EBBCan" is what you call it when you add in the CAN MCU:

Code:
[mcu EBBCan]
serial: /dev/serial/by-id/usb-Klipper_Klipper_firmware_12345-if00
#canbus_uuid: 0e0d81e4210c

You can name the EBBCan whatever you want, but I'd just leave it at defaults. If you change the name, be consistent.
 
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