@Phaedrux The sleeve on the thermistor wire was not covering the final 2 or 3 mm going into the connector shown below.
I do find it curious that this was situated behind the right fan, and also the right fan had died when upgrading. I don't think its possible that the small amount of exposed wire could have shorted anything, there was no room for it to move anywhere.
@Phaedrux Ok so I might be there now!
I separated the wiring from the cable bundle going to the X carriage. I also had decided that while I was unbundling the wires I would replace the right cooling fan that seemed to have died when upgrading to RRF3. I could also see that I had just about fit the thermistor cable extension plug/socket in the gap behind the right fan. I went to check the crimps were ok and also insulate the bare (for a few mm) single core wire going into it with electrical tape but as it was pretty tight in there I managed to break the wire from the crimp. So I soldered the extension on and insulated the join instead and proceeded to test.
With the thermistor separated from the rest I got the below temp chart. There's was a wobble when homing but pretty much fine. I then restarted the print roughly bundling the wires up again with my hands to see if it would play up again and it was also fine.
I have now rebundled all the wires again, and ran the print that would produce the issue every time. Below is the temp graph this time, perfect:
So I think this should be it solved for now but only time will tell using it properly to see if it comes back in certain situations! I do still think the fact that the temperature is jittering at low temps on all sensors doesn't seem normal though and I expect that must have still been related.
Anyway, thank you all for the help, especially @Phaedrux and @Veti, this community really is brilliant.
@hackinistrator I have tried swapping the thermistor to the other extruder input and issue persisted.
Below chart shows that it starts spiking as soon as it starts probing, and is still fluctuating while just printing the slow first layer, then as soon as I pause you can see it smoothly levelling out, I then turn the heater off and it smoothly lowers.
I will try separating wires as much as I can now and will report back.
I am now tuning pressure advance again after retuning e-steps and find that this also causes my temperature to have massive amounts of fluctuations.
I am printing the pressure advance tuning found on this forum, its alternates between 5mm/s and 70mm/s in a straight line which is seeming to cause these temperature fluctuations. Presumably the extruder motor rapidly changing speeds is causing interference with the thermistor.
It's as if there used to be a filter for sensor noise but now any external factors are now causing havoc with the readings. Is there a setting anywhere for gain or noise compensation perhaps? I am wondering if there was a setting defaulted to on that now is not.
Once the calibration print was finished, the temp levelled out to requested temp and remained stable:
@Phaedrux ok I will give that a go soon and see if I can see a difference.
I feel like if the measurement from shorting the thermistor with a jumper was fluctuating like mad instead of a static reading, shows that the noise/fluctuating issue is happening with the board rather than the thermistor wire.
And yes exactly main thing is they seem to be stable when at temp and not probing which is the important bit.
@Phaedrux The thermistors are just simply going to straight from the connectors to the hotend or bed.
All wires going to the X carriage are just simply bundled together though so I guess that is prone to interference. So I guess I should be insulating the thermistor wire from the bl touch and other wires. Weird that this could be causing an issue now after updating but no issue before though.
I used the connectors and crimps that came with the maestro but I wouldn't rule out me not crimping them well.
I think I will just keep using it and see how it goes for now as I see no solution.
I have started a print and can see that despite the temperature seeming unstable at idle, when at temp it levels out to within 0.1 degrees of the requested temperature which is all that matters. I still also get a temperature blip when the bed is probed by the BL touch as shown in the graph below, reporting 15 degrees off within an instant.
It just seems to me that my printer in particular now seems more prone to noise/interference in temp readings than it was before.
I have done a bit of checking for shorts. One thing I have found is that ground and the VSSA pin of all of the thermistors are connected. I am guessing ground and VSSA should be separate?
They are also still joined after unplugging the thermistors.
Edit: Looks like according to this https://duet3d.dozuki.com/Wiki/Connector_and_spare_part_numbers#Section_VSSA_fuse , VSSA and the endstops ground should have under 5ohms between them, it reads 1.8ohm for me so looks correct.
Looking like a hardware or wiring fault then I guess..
Found this from David on an old post: https://forum.duet3d.com/post/128645
I have measured 5v as a stable 4.9v and the 3.3v as stable 3.28v so I think that is ok. So could be one of the other things mentioned like leakage between bed heater and thermistor, I guess if that is the case it would be irreversible.
I guess at this stage the only way of proving it's not a config issue will be reverting back to old firmware with old configs to see if it still does it.
Edit: thought I should also mention that when I was setting up I couldn't get one fan working , on fan02, later realising the fan was just now not working as plugging another in worked fine. Makes me wonder if there was a surge at some point to cause this issue and break that fan at the same time.
@Veti Unfortunately , I have tried the semi automatic ADC tuning and have not seen any improvement. H value for both came up as 0 and L was either -1 or 1.
Interestingly, when I had a jumper over a thermistor , rather than getting a static reading, it was jumping all over the place from 2000c to 10953c. I would have thought this should be a static number. It reported a static -273c when the port was left open which I assume is correct.
Even the CPU temp looks like it's jumping around quite a lot so not sure if there is simply jitter on all sensor readings. (This is also visible on the video in the first post)
Video with a jumper over bed heater to show rapidly changing reading. Record_2020-12-31-14-14-18.mp4
@Veti oh great, I glanced at that and thought it was duet 3 only, yet another thing the maestro has over its duet 2 siblings!
@Veti I have not heard of calibrating ADC before but it does sound promising, a quick browse of the link you sent mentions gain which sounds like a likely culprit for a noisy signal.
I will see if I can get hold of a few resistors to work out the 100k for the H value and a 100. I'll report back once I have tried.
Strange I have the issue now when I didn't on RRF2. Only thing I can think of is I have not set it up or kept it at room temperature like I would have when setting up on RRF2, it's kept in a garage which when I checked it this morning was about 3 degrees!
@Phaedrux just checked, I had actually removed the config override entirely and had never used m500 as anything I wanted changing I have put in the config.
@Veti I will try this, I thought that's exactly how I tuned the PIDs anyway and did it fresh with RRF3.
Still not seeing why PID tuning is relevent to temperatures fluctuating around when idle, no attempt is being made to keep a certain temperature , it's just rapidly changing without input.
@Phaedrux oh, didn't think the config override would change any settings if currently empty anyway. I will remove the m501 as my next test.
That said, I can see the issue of temperature fluctuating when the printer is idling which I would have thought means the PID tuning is irrelevant for this in particular.
@Phaedrux thanks for the reply. I did not use m500 to save the values and instead pasted them in config manually after tuning, do not have anything in the override file.
I have had trouble finding this exact issue in the forums and was hoping someone may be able to point me in the right direction.
I have updated my Duet 2 Maestro to RRF 3.2-RC2 from 2.05 and I am just making sure all is working ok with all the config changes.
My issue is that the temps for bed and hotend are now wildly fluctuating while idle, only within a degree or so but it flicks up and down so quickly that I don't think it can be right, and it did not do this before updating to RRF3. I wouldn't mind this on it's own but pretty sure this is the cause of issue 2:
The other issue relating to this is that I have seen when probing the bed with the BLTouch clone, a large instantaneous temperature decrease may occur, this was very stable before I updated. I have ran PID tuning on RRF3.
I would have thought that both could be explained by interference or failing wires but I had no issues before upgrading to RRF3 and now both thermistors are playing up at once. So I expect I have configured wrong.
I have recorded a video of DWC showing the printer at idle. It's located in a cold room with no fans running:
Record_2020-12-30-23-31-15.mp4
If anyone has any insight as to what might be happening it would be much appreciated, thank you.
; Configuration file for Duet Maestro (firmware version 3)
; executed by the firmware on start-up
;
; generated by RepRapFirmware Configuration Tool v3.2.0 on Mon Dec 28 2020 21:46:20 GMT+0000 (Greenwich Mean Time)
; General preferences
G90 ; send absolute coordinates...
M83 ; ...but relative extruder moves
M550 P"AM8 Duet" ; set printer name
; Network
M551 P"XXXXXXX" ; set password
M552 P0.0.0.0 S1 ; enable network and acquire dynamic address via DHCP
M586 P0 S1 ; enable HTTP
M586 P1 S0 ; disable FTP
M586 P2 S0 ; disable Telnet
; Drives
M569 P0 S0 ; physical drive 0 goes forwards
M569 P1 S0 ; physical drive 1 goes forwards
M569 P2 S1 ; physical drive 2 goes forwards
M569 P3 S0 ; physical drive 3 goes forwards
M584 X0 Y1 Z2:4 E3 ; set drive mapping
M350 X32 Y32 Z32 E16 I1 ; configure microstepping with interpolation
M92 X200.00 Y200.00 Z800.00 E415.00 ; set steps per mm
M566 X300.00 Y300.00 Z12.00 E120.00 ; set maximum instantaneous speed changes (mm/min)
M203 X12000.00 Y12000.00 Z900.00 E3600.00 ; set maximum speeds (mm/min)
M201 X3000.00 Y3000.00 Z150.00 E3600.00 ; set accelerations (mm/s^2)
M906 X900 Y900 Z800 E800 I40 ; set motor currents (mA) and motor idle factor in per cent
M84 S30 ; Set idle timeout
; Axis Limits
M208 X-21 Y-25.6 Z-1 S1 ; set axis minima
M208 X235 Y193 Z260 S0 ; set axis maxima
; Kinematic Type
M669 K0
M671 X296.5:-76.5 Y110.0:110.0 S5 ; Z leadscrews are at
M569 P2 V100 ;Quiet Z Axis
M569 P4 V100 ;Quiet Z Axis
; Pressure advance. DAA
M572 D0 S0.07 ; Pressure advance was 0.18
M593 F42.85 ; 42.85hz DAA
; Endstops
M574 X1 S1 P"!xstop" ; 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"^zprobe.mod" ; create servo pin 0 for BLTouch
M558 P9 C"^zprobe.in" R0.05 H4 F80 A5 S0.02 T6000 ; set Z probe type to bltouch and the dive height + speeds
G31 P500 X-28.9 Y-33.5 Z1.15 ; set Z probe trigger value, offset and trigger height
M557 X30:190 Y30:190 S40 ; define mesh grid
; Heaters
M308 S0 P"bedtemp" Y"thermistor" T100000 B4138 ; 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
M307 H0 R0.274 C461.1 D3.36 S1.00 V13.0 B0 ; Tuned M307
M140 H0 ; map heated bed to heater 0
M143 H0 S120 ; set temperature limit for heater 0 to 120C
M308 S1 P"e0temp" Y"thermistor" T100000 B4725 C7.06e-8 ; configure sensor 1 as thermistor on pin e0temp
M950 H1 C"e0heat" 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
;M307 H1 R2.594 C192.6 D5.08 S1.00 V13.2 B0 ; Tuned M307
M307 H1 R2.520 C195.7 D4.99 S1.00 V13.2 B0 ; Tuned M307
M143 H1 S280 ; set temperature limit for heater 1 to 280C
; Fans
M950 F0 C"fan0" Q10 ; create fan 0 on pin fan0 and set its frequency
M106 P0 S0 H-1 C"Left" ; 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 T30 ; set fan 1 value. Thermostatic control is turned on
M950 F2 C"fan2" Q10 ; create fan 2 on pin fan2 and set its frequency
M106 P2 S0 H-1 C"Right" ; set fan 2 value. Thermostatic control is turned off
; Tools
M563 P0 D0 H1 F0:2 ; 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
M501 ; load saved parameters from non-volatile memory
Edit: forgot to mention, the hotend is genuine e3d V6 with standard thermistor and bed is a generic Chinese 12V.
I thought I would just follow up with what I have done based on the comments here. I have made some ducts that I tried to restrict the air flow as little as possible. They attach around the end of the fan instead of inside of the fan to restrict air flow less. Also I tried to keep the area of the the duct as large as possible to constrict flow as little as possible.
When turning the fans on and feeling with my hand the airflow feels much better than before. The overhang quality seems much better but I have limited testing for now and I think I can improve further.
Unfair test as different filament but yellow is before green after, up to 80 degree overhang.
@jens55 Z axis may be binding? If the Z axis uses two lead screws, make sure the X axis is perpendicular/ Level with the Z axis. If the Z axis is binding it can cause one side of Z to go up when the other side is stuck, causing the layers to look wonky.
@Visionary Thanks, I run 12V so the B5015E12B-BSR looks to be the equivalent with the same CFM and pressure. Really useful that they actually show proper specifications so that looks hopeful. I have not had all these specs available where I have purchased before and any info that was given is unlikely true. Only thing I can use as reference is that the B5015E12B-BSR is 12V 0.3a when what I have is 12V 0.15a or 0.18a so that's got to count for something. I will not mind about noise if they cool well!
@arhi Thanks, I see I need to go for simplest possible redirection towards the nozzle. I have basically come to this conclusion before but am amazed how much flow is lost even with a very simple duct. I think where I have gone a little wrong is how low down the blower fans are, requiring quite a bit of redirection over not much distance. The ducts also mount by pushing into the end of the blower fan so I better check if that's having a negative effect too.