Duet WiFi firmware new feature priorities
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CC test is usually only in a single direction, Astrom-Hagglund is bidirectional, I would suggest with CC that you do both a heating and cooling step test and use the average result, both CC and Astrom-Hagglund will require that you give the PID function a manual mode of operation, and Id also recommend a bump-less transfer function.
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I really don't even think you need the P term if you have a good heat flux model, FF+I should do it. Proportional feedback makes hot blocks with a lot of sensing lag or very small heat capacity more oscillatory. But it's literally one line of code to include, so there's probably no downside to leaving it in there. Easy enough to set the P gain to 0 if you don't like it.
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The effectiveness of the D term here GREATLY depends on the selection of temp change filtering. For example, a while back, Smoothieware was updating the PID at 20 Hz, scaling the temp change back to degrees/second units for D (ie multiplying the last 0.05 seconds of temp change by 20), and had zero filtering/averaging within the PID loop… so EVERY time the temp changed, the D term would kick like a mule and saturate the entire PID output to 0% or 100%, then go back to doing nothing 0.05 seconds later. Without a low-pass or lag-cut filter or whatever, the D term was doing significantly more harm than good. (I think they fixed that, I haven't looked lately. I know they implemented better ADC filtering to reduce the noisy stepwise temp changes they were getting due to bad ADC hardware on the LPC17xx.)
In comparison, if you have an appropriate moving average or whatever filter, the D term really helps tamp down on hot end temp oscillation and overshoot. Having the D term update faster than the time constant of the temp sensor (which is maybe 2-3 seconds for a glass bead thermistor) is pretty stupid.
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I just had a random curiosity question come to mind.
Is there any easy way to switch between types of thermocouple on the TC expansion board, or is the lookup table (and hopefully the cold junction compensation) hard coded into the interface chip on the expansion board?
If this is accessible to be patched or changed through the firmware updating process, it might be a useful option.The reason I ask is that some have easier access to different metalurgies, such as Type J, and in the case of Type J, it can be more accurate in the range we should see as well.
Again, this is just curiosity, and very late to the game to be bringing up feature requests.
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I just had a random curiosity question come to mind.
Is there any easy way to switch between types of thermocouple on the TC expansion board, or is the lookup table (and hopefully the cold junction compensation) hard coded into the interface chip on the expansion board?
If this is accessible to be patched or changed through the firmware updating process, it might be a useful option.The reason I ask is that some have easier access to different metalurgies, such as Type J, and in the case of Type J, it can be more accurate in the range we should see as well.
Again, this is just curiosity, and very late to the game to be bringing up feature requests.
The conversion table is built into the MAX31855K chip on the TC expansion board. To use a type J thermocouple, you would need to use a MAX31855J instead of MAX31855K. I could build you a special if you want. If you want to assemble your own, we could probably let you have a bare PCB.
I guess it would be possible to do the conversion in firmware, but unless several users want it, it is unlikely that I will implement that. The nice thing about the MAX31855 is that by using the chip matched to the thermocouple, the chip does all the work and the firmware just reads the temperature from it. Type K thermocouples are widely available and inexpensive.
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That makes sense. I didn't know how you were implementing the TC reading, or I wouldn't have bothered you.
If there is an un-populated board available, I would be interested in giving it a try. This does sound like a much simpler solution than how my work handles TCs, but I'm guessing that the Maxim chip may not have as much ability to be calibrated for precision and documentation of the same.
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That makes sense. I didn't know how you were implementing the TC reading, or I wouldn't have bothered you.
If there is an un-populated board available, I would be interested in giving it a try. This does sound like a much simpler solution than how my work handles TCs, but I'm guessing that the Maxim chip may not have as much ability to be calibrated for precision and documentation of the same.
You can find the datasheet at https://datasheets.maximintegrated.com/en/ds/MAX31855.pdf. The accuracy figures are on pages 3 and 4.
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I like to add other requests to the list:
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Filament Odometer ( keeps traking of the amount of filament the printer use since: last print/last startup/commissioning)
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Time Odometer ( keeps traking of the amount of time the printer use since: last print/ last startup/commissioning)
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Support Volumetric Extrussion
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Emergency Stop Button in PanelDue
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Filament sensor: support to 3 types of sensors:
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The implementation of a switch to see if I'm out of filament.
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The implementation of a "mouse wheel " attached to the filament to check if the filament if moving and how much it's moving (If the wheel is not moving, there is no more filament or the hotend is jam )
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A ccd sensor to check filament diameter to dinamicaly execute M200 gcode to change filament diameter to allow volumetric extrusion (http://www.thingiverse.com/thing:699308 and [[url=http://www.thingiverse.com]www.thingiverse.com] )
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I've spoken to David previously about adding support for a simple switch based filament out sensor to the PanelDue so that you don't have to run as many wires (I'm on a delta and the PanelDue is right next to my spools).
If you have any interest in that please chime up.
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Just an idea,
I was thinking of making an "Air Struder" for a large build kossel. But although it's a proven solution the weight of the extruders are still mostly on the carriages.
An alternative is balancing with springs but it is not my favorit solution either.
It might not be much weigh for 2-4 extruders but if you consider a reservoir for paste extrusion it can be 1 kilograms or 2.
Why not suspend the effectors/paste reservoir to an extra stepper motor with a pulley and have them raise as a function of the current printed layer. So the vertical distance between effector and the airstrudder would stay constant. Basically a height controlled hanging platform about 40 cm above the effector. -
I like to add other requests to the list:
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- A ccd sensor to check filament diameter to dinamicaly execute M200 gcode to change filament diameter to allow volumetric extrusion (http://www.thingiverse.com/thing:699308 and [[url=http://www.thingiverse.com]www.thingiverse.com] )
This would be awesome!
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For me, the biggest things would be:
- Digital Filament sensor support. (I have a tunell sensor on my Smoothie. It would be a killer to lose the ability to have large print pause resume capability. I'd go back to having tons of partial rolls of filament lying around!)
- Config override file
- Predictive Temperature Control
- Babystepping
- I don't have a number 5!
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You can already use digital filament sensors. See http://reprap.org/wiki/G-code#M581:_Configure_external_trigger. I'll write a wiki page about using this facility with filament out sensors when I get time.
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I described a simple switch based filament detection here :
http://reprap.org/wiki/RepRap_Firmware_macros#Set_of_macros_for_filament_detectionI published details and photos here: http://forums.reprap.org/read.php?416,668887,668887#msg-668887
However, I have yet to publish the stl and scad for the modified tensioner -
@dc42 My apologies. Everything I'd seen to this point (including this thread) seemed to indicate it wasn't yet a feature (reading comprehension fail).
Can it ignore the sensor when not actually printing? When my print is finished, the Tunell sensor will trigger a non-moving condition. As a result, the switch would be triggered until I reset it. This would cause the system to go to the "pause position" while at home and that's not so awesome of a result on a Delta printer.
A valid answer is, dump the fancy electronic sensor for one that doesn't trigger unless it's out of filament but I hope that's not the one you give me.
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I' ll add to the list a "region extrude inhibit" some times a piece comes off of the bed, if I can do a region extrude inhibit, I can pause the printer, remove the piece that comes off mark a region and inhibit the extrude in that region. when the print finish i can print the piece that fail
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I've spoken to David previously about adding support for a simple switch based filament out sensor to the PanelDue so that you don't have to run as many wires (I'm on a delta and the PanelDue is right next to my spools).
If you have any interest in that please chime up.
Is a cool feature. I have the panel due in the printer's bottom. For me is the same to wire from duet or from panel due (in my setup I prefer from duet )
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@dc42 My apologies. Everything I'd seen to this point (including this thread) seemed to indicate it wasn't yet a feature (reading comprehension fail).
Can it ignore the sensor when not actually printing? When my print is finished, the Tunell sensor will trigger a non-moving condition. As a result, the switch would be triggered until I reset it. This would cause the system to go to the "pause position" while at home and that's not so awesome of a result on a Delta printer.
A valid answer is, dump the fancy electronic sensor for one that doesn't trigger unless it's out of filament but I hope that's not the one you give me.
If you follow the link to the gcode wiki in my previous post, you will see that the M581 command has an option for the trigger to be recognised only while printing from SD card.
M581 is recently implemented and not much used yet. Please let us know how well it works with your Tunell filament sensor.
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Another Request:
Add a switch to M117 Gcode to allow send de message via email (to check via email if the printer started to print or the print finished for example)
M117 S"This is the subject" -D"john@example.com" -B"This is the message body"
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Just got mine. Luverly..
Can the BL Touch probe be added.
Steve a newbe
