Posts made by Frederik561

@dc42
Thank you! Helps a lot. Really appreciate the fast answers

@dc42
Okay, thank you. I don't have any issues making it work as intended. I have inverted in M950 and it works fine. I have set the standby temperature to 35 degrees and it does not turn on at startup. When activated to reach 10 degrees, the heater turns on and holds the required temperature perfectly. Before printing, I wait before the temperatures are reached instead of relying on the board to wait for the correct temperature to be reached, so that should not be a big issue. I am using the system you describe to smooth the PWM

In M307 the possibility for connecting a peltier module for cooling is even mentioned (inversion happens in M950 though).

It works when connected to the e1 heater and draws 3 amps when activated. 4 motors have set limits to 1 amp each and the nozzle heater draws about 1 amp as well. Is it likely that the 7.5A fuse will break?
If yes, is it okay to replace the 7.5A bladefuse with a 10A instead? Will more than 7.5A in that channel damage the board? (Duet 2 wifi)

@dc42

1. I am certain. I have tried removing the inversion and it still happens
2. I intend to cool the bed to 10 degrees C. Should be possible with 12V and 3-4 amps.
3. It is for a bioprinter. Basically a normal 3D printer that prints into a cool petri dish
4. I have tried some different peltier elements. Currently I am using a TEC1-12706 model with 2 Ohms resistance at 25 degrees C. This resistance increases with increased temperaturdifference, meaning I will always draw less than 6 amps. I have an ACR712 measuring the current at all times using an arduino

I am now using the e1 heater output with the peltier module and it works fine with bang bang. I have nothing else connected and as I understand it, the limit is 7,5A right? It will limit the amps to the peltier element with each motor drawing 1 amp and the nozzle heater drawing about 1 amp as well (only have to heat to 37 degrees C). So only about 2,5 amps max to the peltier element?

@Veti
Ok, thank you. I have never tried to work with 3D printers before, and I don't think I had any ways of knowing that in advance. I wrote the config-file before the post was made in september and it only just gave up now, so I thought everything was fine.

Guess I have to buy a new duet 2 wifi? I don't suppose the problem can be fixed?

@jay_s_uk
Any way to fix it? And is the same mosfet used for all heaters or can I still use the nozzle heater?

@Veti To make a more even current. A peltier module does not work well with a low frequency. The limit is 65535 Hz so I thought the MOSFET would be capable of doing that.

@jay_s_uk

Inverting because I am using a peltier module to cool down. And the heater stays on even when removing the SD card. I suppose that is a bad thing?

Hello
I have a problem with my bedheater. It wont turn off and the red indicator is always on even though it detects fault and is turned off in the duet web control. I am using it with a peltier module to cool the bed down, but that is not the problem. Even if I configure it as a normal heater, it will always be on. Can anyone help with this?

/Frederik

Hello

I have a problem using the M307 S command. I am using a peltier module to cool down the bed and it works fine when S1 is used. However, if I use for example S0.5, the heater (cooler) is just turned on at all times. Any idea why that is?

Thanks in advance
/Frederik

@Phaedrux Thank you for answering! About the probe in a radius, how do I define the point around which the radius is taken (the center)?

Hey
I am currently working on my project for my bachelors degree and I am due to quarantine unable to test whether my G-code works.

Background:
I am making a cartesian printer for bioprinting similar to this: https://all3dp.com/2/what-is-3d-bioprinting-simply-explained/

I have mounted a FSR on top of the syringe, so that when the needle touches the bed, it will get squeezed and register and can therefor be used for bed probing. The Z-endstop is at the top, so it will only be used for bed probing. The trigger height will be measured once I am allowed access to my university.

The bed is designed to attach either a petridish or different sizes multiwells: https://www.sigmaaldrich.com/catalog/product/sigma/m8562?lang=en&region=DK&gclid=CjwKCAiA17P9BRB2EiwAMvwNyHDWWf2rC0ZpnNOAkNs0A3OEAbc-PecdWQ6XL4AD6bRXAWmXKzU44hoCC8oQAvD_BwE.

Depending on whether a petridish or multiwell (and what size) is mounted, I want to be able to choose different bed probings.

Multiwell bed probing
For the multiwell I have the current setup in the G-code:
---In the config.g file---
M558 P8 C"!^zprobe.in" I1 H30 F50 T200 -; Defining type and speeds + dive height
G31 P500 X0 Y0 Z-3--------------------------------; Guessing trigger height (for now)
M557 X50:80 Y50:80 S15------------------------ ; Arbitrary grid for some multiwell

---In bed.g fil--- (run by G32)
G28-------------------------------------------------; Homing
G30 X62.6 Y41----------------------------------; Single probe in an arbitrary hole for Z=trigger height datum
G29-------------------------------------------------; Probing and mesh bed compensation

Questions for multiwell
1.1: Does this method work in general?
1.2: I have set the dive height to 30 mm. Does it mean that it will raise 30 mm between every probe? I have to make sure it clears the edge of the multiwell between each probe point because it will make a probe in each hole.

Questions for petri dish
I want to make probing at the radius. I just cant figure out how to do this properly and in which files to put the different commands. I was thinking about just making a macro file including all the commands, but I am not sure which ones to use.

2.1: Can I somehow use the M557 R-command to probe in a radius around the middle of the petri dish (middle is placed at X62.6 Y41) and use G29 to execute it?
2.2: If not, can I use M557 P to define a series of points to probe at? And can G29 be used afterwards to execute the probing and enable bed compensation?

Thanks in advance!

Hello
I am currently working on a 3D printer to be used in medical research. It uses standard high end component used in 3D print in general. I have chosen to use the Duet 2 Wifi board for the application because of the quality and smooth stepping.

The only difference from a normal 3D printer is that the bed has to be cooled to about 4°C instead of being heated. For that I am using a 12V peltier element beneath the bed and a buck converter to go from 24V to 12V.
This is not supported by the current G-code, but I am wondering if it is possible to tweak the G-code to hit the lower temperature using PID regulation.

Any ideas may help

/Frederik