Custom Heat Pad and thermistor question
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Looking here at the link suggested for setting up the bltouch, https://duet3d.dozuki.com/Wiki/Test_and_calibrate_the_Z_probe , it says on step 10
Open config-override.g and check that there are no G31 commands in it. If you find any, delete those lines and save the file.I do not have a config-override.g file. Should I?
- Board: Duet 2 WiFi (2WiFi)
Firmware: RepRapFirmware for Duet 2 WiFi/Ethernet 3.2.2 (2021-02-11)
Duet WiFi Server Version: 1.25
- Board: Duet 2 WiFi (2WiFi)
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@wingtip said in Custom Heat Pad and thermistor question:
I do not have a config-override.g file. Should I?
It will get created after sending M500 to save any measured values. If it doesn't exist, don't worry about it. When you do the bed and nozzle heater tuning you'd usually send M500 to save those results. You'd also need to put M501 at the end of config.g to load that file again at startup.
https://duet3d.dozuki.com/Wiki/Gcode#Section_M500_Store_parameters
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ok, i have the z offset set (not perfect till i try a print), and have the x,y offsets in. I have not done any pid tuning yet. should i wait to put the m501 into the config.g till i do the pid tuning?
and with the bl touch working now can i try some sort of mesh leveling to try to dial in the bed mechanical adjustments?? -
Yes if you've got the BLtouch working with G30 now you can do mesh leveling if you wanna see you the bed surface looks.
M557 controls the area to probe and the density of points.
You can add M501 now or wait until after you do the tuning. Up to you. BTW, be prepared to wait a while for the bed tuning to complete. It can take a long time with large beds. It'll be interesting to see how it deal with the unorthodox setup.
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I think i am ready to try to heat up the bed.... Bare with me for all the dumb questions because 1) this is my first duet/reprap (coming from marlin), 2) My first AC powered bed with SSR..
I will post the config g below if someone can take a look at the heater section and make sure all looks good. If so i think the first command i want to enter to the console would be something like:- M303 T0 S100 ; where T0 is the bed and S80 is the cutoff or target temp??? Is this correct?
Configuration file for Duet WiFi (firmware version 3) ; executed by the firmware on start-up ; ; generated by RepRapFirmware Configuration Tool v3.2.3 on Wed Mar 03 2021 15:26:56 GMT-0600 (Central Standard Time) ; General preferences G90 ; send absolute coordinates... M83 ; ...but relative extruder moves M550 P"The Big One" ; set printer name ; Network M552 S1 ; enable network M586 P0 S1 ; enable HTTP M586 P1 S0 ; disable FTP M586 P2 S0 ; disable Telnet ; Drives M569 P0 S0 ; physical drive 0 goes reverse M569 P1 S0 ; physical drive 1 goes reverse M569 P2 S1 ; physical drive 2 goes forwards M569 P3 S0 ; physical drive 3 goes reverse M569 P4 S1 ; physical drive 4 goes forwards M569 P5 S0 ; physical drive 5 goes reverse M584 X0:3 Y1 Z2:5 E4 ; set drive mapping M350 X16 Y16 Z16 E16 I1 ; configure microstepping with interpolation M92 X395.52 Y80.00 Z400.00 E420.00 ; set steps per mm M566 X300.00 Y900.00 Z180.00 E120.00 ; set maximum instantaneous speed changes (mm/min) M203 X4000.00 Y4000.00 Z400.00 E1200.00 ; set maximum speeds (mm/min) M201 X400.00 Y500.00 Z20.00 E250.00 ; set accelerations (mm/s^2) M906 X1400 Y1000 Z1200 E800 I30 ; set motor currents (mA) and motor idle factor in per cent M84 S30 ; Set idle timeout ; Axis Limits M208 X0 Y0 Z0 S1 ; set axis minima M208 X655 Y440 Z400 S0 ; set axis maxima ; Endstops M574 X1 S1 P"!xstop+!e0stop" ; configure active-high endstop for low end on X via pin xstop M574 Y1 S1 P"!ystop" ; configure active-high endstop for low end on Y via pin ystop M574 Z1 S2 ; configure Z-probe endstop for low end on Z ; Z-Probe M950 S0 C"duex.pwm3" ; create servo pin 0 for BLTouch M558 P9 C"^zprobe.in" H5 F120 T6000 ; set Z probe type to bltouch and the dive height + speeds G31 P500 X0 Y-35 Z2.757 ; set Z probe trigger value, offset and trigger height M557 X15:215 Y15:195 S20 ; define mesh grid ; Heaters M308 S0 P"bedtemp" Y"thermistor" T100000 B3950 ; configure sensor 0 as thermistor on pin bedtemp M950 H0 C"bedheat" T0 ; create bed heater output on bedheat and map it to sensor 0 M307 H0 B0 S1.00 ; disable bang-bang mode for the bed heater and set PWM limit M140 H0 ; map heated bed to heater 0 M143 H0 S120 ; set temperature limit for heater 0 to 120C M308 S1 P"e1temp" Y"thermistor" T100000 B4725 C7.06e-8 ; define E1 temperature sensor M950 H1 C"e1heat" T1 ; create nozzle heater output on e0heat and map it to sensor 1 M307 H1 B0 S1.00 ; disable bang-bang mode for heater and set PWM limit M143 H1 S280 ; set temperature limit for heater 1 to 280C ; Fans M950 F0 C"fan0" Q500 ; create fan 0 on pin fan0 and set its frequency M106 P0 S0 H-1 ; set fan 0 value. Thermostatic control is turned off M950 F1 C"fan1" Q500 ; create fan 1 on pin fan1 and set its frequency M106 P1 S1 H1 T45 ; set fan 1 value. Thermostatic control is turned on ; Tools M563 P0 D0 H1 F0 ; define tool 0 G10 P0 X0 Y0 Z0 ; set tool 0 axis offsets G10 P0 R0 S0 ; set initial tool 0 active and standby temperatures to 0C ; Custom settings are not defined ; Miscellaneous M575 P1 S1 B57600 ; enable support for PanelDue T0 -
M303 T0 S100 would tune the hotend heater on tool0 to 100c. T0 = tool0. This will also control the part cooling fan automatically to take it's cooling of the nozzle into account.
The bed would be M303 H0 S100. H0 = heater 0, which in your config is the bed.
But I think you should tune the hotend heater first so you can see what to expect. Just choose your normal printing temp.
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@phaedrux said in Custom Heat Pad and thermistor question:
M303 H0 S100.
I dont have a part cooler yet for this so should i still try a tune on the hotend? Then try the bed?
M303 H1 S236 ; for the hotend
M303 H0 S80 ; for the bed, should i use a p variable for the pwm setting or does it just default to full 100% pwm?? -
Yeah if you don't have a part fan at the moment you can just use M303 H1.
PWM is 100% by default.
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@wingtip said in Custom Heat Pad and thermistor question:
M303 H1 S236
I forgot to install the heater block sock but here are the results from the hotend pid tuning
Auto tuning heater 1 completed after 3 idle and 5 tuning cycles in 395 seconds. This heater needs the following M307 command: M307 H1 R1.856 C216.2 D4.86 S1.00 V11.8 Edit the M307 H1 command in config.g to match this. Omit the V parameter if the heater is not powered from VIN. -
@wingtip nozzle sock and tuning it as a tool will be a good idea once that's all in place, but that's a good first step. Show's it heats up anyway. If you set a temp does it hold steady?
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@phaedrux yes but i already knew that when i heated it up to tighten the nozzle
so im good to copy that m307 line in its entirety to the config file and save? then do pid tuning on the bed or should i do it now and enter both lines then save and restart?
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Either copy the line or just send M500 to automatically save the results to config-override.g. Then add M501 to the end of config.g to load that file. Whichever you prefer.
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Well I had some interesting things happen while trying to PID tune the bed. Being worried about heating up the glass to quickly as this was my first ac powered bed, when i sent the command to start the tune i also entered a P command to cut the pwm to 40% to ease into heating up the glass. It was very slow to say the least but it was heating up. When it first put power to the bed it had a slight odor to it that i just assumed was the new pad.
Eventually it got up to about 60c (i set it to go to 80c) then failed saying that the temp couldnt be reached. Im unaware if it was at that moment is when the failure occured or when i tried again later after letting the bed cool fully and i then let it rip at full pwm In hopes that it just timed out the first time and would heat faster at 100%. But after noticing finally the power switch to the bed wasnt lit i removed the switch and found the fuse had melted the internal plastic around it and eventually blew. the fuse internally was only 5 amp. I need to find a new switch that can handle a little more amperage. I wouldnt trust re using this one with a new fuse since the housing got so hot.
This is the switch i used (bought 2 years ago for this project) https://www.amazon.com/gp/product/B07C1567XW/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1
and here was the results
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Well let's see, you installed a switch/fuse/socket combo that has a 5A fuse installed with a switch that is rated at 10A and you run between 12 and 13A (depending on your line voltage) through it.
Can you see a problem with this arrangement?
Find yourself something that is rated at 20A and you will be golden.
BTW, the power cords that plug into that particular plug are usually rated at between 5 and 10A and make for a nice heater when you draw that much power .... but then you like to do unconventional things so don't let me keep you from exploring this method of powering your printer. Like the arrangement of your print bed, it likely will work for a while before biting you in the rear. -
@jens55 as i said i bought the switch 2 years ago and its been installed for a year or so... Of course i see the problem now
Im already looking at a new switch and some assorted fast blow fuses better suited that will be ordered shortly.
Not sure why your being such a prick about my way i built the bed.... it will work and has been working on my other printer for years.... but by all means continue shaming something different. I dont care if it does fail, at least im experimenting and having fun... -
@wingtip, trying to explain why I am giving you a hard time will come across as snarky so I will not explain myself.
On the other hand, in the spirit of trying to help - do not install fast blow fuses, they are inappropriate for this application.
Saying "I don't care if it does fail ...." is fine in low voltage low power situations but not when you are playing with line voltage and high power heaters. Failure has the distinct possibility of burning down your house...
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Now now, no need to be snarky here. Pretend it's a maker space and we're all just here to help each other out and learn while we go.
@wingtip that sucks. At least the fuse did what it was supposed to eventually. Likely a slow blow version.
Replacing the socket entirely would be a safe bet. Getting a fuse rated for the draw obviously.
Given the draw of the bed it might be a good idea to put it on it's own fused socket.
I should have asked about that detail earlier on.
@jens55 said in Custom Heat Pad and thermistor question:
do not install fast blow fuses, they are inappropriate for this application.
I'm curious about this. I've been using a "fast blow" fuse on my bed heater and it hasn't been an issue. Fast blow still isn't very "fast". Is the concern that it would blow too quickly?
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@phaedrux, yes, fast blow fuses blow .... well ... fast
If you were to measure the cold resistance on your bed heater and calculate the current based on that rather than the normal operating current, then you get the minimum fuse size for that heater for a fast blow fuse. A regular fuse can be rated based on the operating current of the heater.
There are very few instances when a fast acting fuse is used and you usually pay a premium for them.
A regular fuse will allow for start up surges such as charging up large filter capacitors or heater start up current but will still protect the integrity and safety of the electrical system. A fuse will have specifications how long it will take to pop at how much overcurrent. A regular fuse is just more tolerant of surges and odd events while still making sure that the supply wiring will not be overloaded.
If you use a fast acting fuse but over-rate it (ie a 10 amp fuse when your normal draw is 5A), the fuse will tolerate start up surges and work just fine but you paid a premium for no additional protection.
I am sure there are other reasons that I am not aware of at the moment. -
Further to my comments about electrical safety .... one needs to look at the whole system and not just an individual component. If you design a circuit at that kind of voltage/power level, you need to be aware of the details of the entire system. Replacing the inlet receptacle with a version that handles 20A will not help you if the cord from the receptacle to the wall is only rated for 10A (or less). Ampacity charts are readily available.
It is bad ju ju if one is designing and building stuff related to line power without being fully aware of all the details. If you throw in the use of Chinese components, you really need to have a good understanding of what is what.
As an example of that, Chinese SSR's are known to be over-rated so the prudent designer would use either a 20A rated brand name device or a 40A (or higher) Chinese no name or clone brand. In both cases it is good policy to use a heat activated fuse on the bed in addition in case the doo doo hits the fan. Again, shit like this can easily burn down your house. -
I would like to add that using a fuse that is rated at a much higher draw then what you normally use (and using a higher rated fast blow in order to not trip it) is not recommended for obvious reasons.
