Thermocouples for Duet
Posted by HWrp156
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Thermocouples for Duet January 20, 2016 07:47AM |
Registered: 8 years ago Posts: 23 |
I have recently purchased the 'Type K Thermocouple (Welded Tip)' from E3D-Online along with the 'External Thermocouple Board v1.0'. I was hoping to integrate these into my Ormerod 2 system, however can't see any schematics on how to connect them to a Duet version 0.8.5? Are they compatible or does it have to be Ramps? I assume the same connection method can be done for both controller boards, however do not want to start in the case of creating multiple faults.
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Re: Thermocouples for Duet January 20, 2016 03:35PM |
Registered: 10 years ago Posts: 14,672 |
See [reprap.org] for how to use thermocouples with the Duet.
Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod
Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod
Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
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Re: Thermocouples for Duet January 20, 2016 04:30PM |
Registered: 8 years ago Posts: 31 |
Hi, what are the advantages of thermocouples over the 100k ohm thermistors in our application ?
Regards,
Julian S.
T3DP3D Mini Kossel, E3D V6 hot end, 0.4mm nozzle, 200mm diameter Ali heated bed, Duet v0.8.5 & dc42 rep rap v1.18. DWC v1.15, PanelDue-7-1.16 DC42 IR Z Probe, 2 X MAX31855 &Thermocouples, PID heated enclosure, SolidWorks 2017, slic3r
Regards,
Julian S.
T3DP3D Mini Kossel, E3D V6 hot end, 0.4mm nozzle, 200mm diameter Ali heated bed, Duet v0.8.5 & dc42 rep rap v1.18. DWC v1.15, PanelDue-7-1.16 DC42 IR Z Probe, 2 X MAX31855 &Thermocouples, PID heated enclosure, SolidWorks 2017, slic3r
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Re: Thermocouples for Duet January 20, 2016 05:32PM |
Registered: 10 years ago Posts: 14,672 |
There are at least two advantages of using thermocouples over thermistors. The first is that they can be used at higher temperatures. Thermistors are usually limited to 300 or lower, which is fine for PLA, ABS and PETG but too low for some specialist filaments.
The second is that they are more accurate and more reproducible. The MAX31855 chip used in thermocouple boards suitable for the Duet quotes an accuracy of +/- 2C. Whereas thermistors have a resistance and B value tolerance, so does the series resistor, and there may be other errors introduces by the ADC in the main processor and the lack of a separate analog ground on some popular printer electronics.
However, accuracy is not that important if you have just one printer, because you will need to experiment to find the best temperatures anyway. It may be different if you have several identical printers and you want settings to be transferable between printers.
Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod
Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
The second is that they are more accurate and more reproducible. The MAX31855 chip used in thermocouple boards suitable for the Duet quotes an accuracy of +/- 2C. Whereas thermistors have a resistance and B value tolerance, so does the series resistor, and there may be other errors introduces by the ADC in the main processor and the lack of a separate analog ground on some popular printer electronics.
However, accuracy is not that important if you have just one printer, because you will need to experiment to find the best temperatures anyway. It may be different if you have several identical printers and you want settings to be transferable between printers.
Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod
Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
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Re: Thermocouples for Duet January 21, 2016 09:53AM |
Registered: 8 years ago Posts: 23 |
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Re: Thermocouples for Duet January 21, 2016 02:09PM |
Registered: 10 years ago Posts: 14,672 |
The expansion connector is the long 2 x 25 header pin strip along one edge of the Duet.
Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod
Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod
Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
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Re: Thermocouples for Duet January 29, 2016 12:48PM |
Registered: 8 years ago Posts: 23 |
Hi again, so I have purchased the board and connected up according to the RepRap wiki page. However it doesn't seem to give me a temperature reading on Pronterface and instead just states -48.8 degrees. I have connected up the correct pins (with CS as pin 11) and used the M305 P1 X102 command but it just responded with lots of text. Is there something I am missing?
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Re: Thermocouples for Duet January 29, 2016 03:03PM |
Registered: 10 years ago Posts: 14,672 |
I had something similar until I added the 10nF capacitor across the thermocouple input terminals, because the MAX31855 board I purchased didn't have it already fitted. So check whether the capactor is present on your board. You need to use my 1.09r-dc42 firmware version, or one of Dan Newman's releases.
Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod
Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod
Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
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Re: Thermocouples for Duet January 29, 2016 03:17PM |
Registered: 8 years ago Posts: 31 |
Hi,
I'm after a dual thermocouple pcb based on the max31855.
I've not been able to find one on eBay.co.uk etc.
Please post a link if you see any in the uk or Europe.
Thanks.
Regards,
Julian S.
T3DP3D Mini Kossel, E3D V6 hot end, 0.4mm nozzle, 200mm diameter Ali heated bed, Duet v0.8.5 & dc42 rep rap v1.18. DWC v1.15, PanelDue-7-1.16 DC42 IR Z Probe, 2 X MAX31855 &Thermocouples, PID heated enclosure, SolidWorks 2017, slic3r
I'm after a dual thermocouple pcb based on the max31855.
I've not been able to find one on eBay.co.uk etc.
Please post a link if you see any in the uk or Europe.
Thanks.
Regards,
Julian S.
T3DP3D Mini Kossel, E3D V6 hot end, 0.4mm nozzle, 200mm diameter Ali heated bed, Duet v0.8.5 & dc42 rep rap v1.18. DWC v1.15, PanelDue-7-1.16 DC42 IR Z Probe, 2 X MAX31855 &Thermocouples, PID heated enclosure, SolidWorks 2017, slic3r
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Re: Thermocouples for Duet January 29, 2016 03:27PM |
Registered: 10 years ago Posts: 14,672 |
If you expand your search to include international sellers, you will find dual and quad boards that ship from USA. Or you can use two single boards.
Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod
Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod
Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
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Re: Thermocouples for Duet January 31, 2016 02:01PM |
Registered: 8 years ago Posts: 31 |
Thanks Dave.
I might try and knock up a dual circuit myself.
The MAX31855 devices are available from Farnell etc as well as SOIC to DIP adapter pcbs.
I can solder SOIC at home but nothing smaller like TSSOP etc. Although we have a stereoscopic microscope at work and smt rework station.
Just need to check into differing metal junctions that might upset the K type thermocouple readings.
In-line thermocouple connectors tend to be large so I am thinking the nozzle thermocouple wires should be one piece.
Regards,
Julian S.
T3DP3D Mini Kossel, E3D V6 hot end, 0.4mm nozzle, 200mm diameter Ali heated bed, Duet v0.8.5 & dc42 rep rap v1.18. DWC v1.15, PanelDue-7-1.16 DC42 IR Z Probe, 2 X MAX31855 &Thermocouples, PID heated enclosure, SolidWorks 2017, slic3r
I might try and knock up a dual circuit myself.
The MAX31855 devices are available from Farnell etc as well as SOIC to DIP adapter pcbs.
I can solder SOIC at home but nothing smaller like TSSOP etc. Although we have a stereoscopic microscope at work and smt rework station.
Just need to check into differing metal junctions that might upset the K type thermocouple readings.
In-line thermocouple connectors tend to be large so I am thinking the nozzle thermocouple wires should be one piece.
Regards,
Julian S.
T3DP3D Mini Kossel, E3D V6 hot end, 0.4mm nozzle, 200mm diameter Ali heated bed, Duet v0.8.5 & dc42 rep rap v1.18. DWC v1.15, PanelDue-7-1.16 DC42 IR Z Probe, 2 X MAX31855 &Thermocouples, PID heated enclosure, SolidWorks 2017, slic3r
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Re: Thermocouples for Duet January 31, 2016 04:40PM |
Registered: 10 years ago Posts: 14,672 |
Yes, you need either single-piece leads back to the MAX31855 board, or a proper thermocouple extension lead designed for use with K-type thermocouples - but as you say, the connectors tend to be large.
Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod
Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod
Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
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Re: Thermocouples for Duet January 31, 2016 04:46PM |
Registered: 10 years ago Posts: 14,672 |
PS - for some time I have been considering making small boards that mount on the hot end and do the temperature measurement and control. The main aim is to reduce the number of wires from the hot end to the main electronics when 2, 3 or 4 nozzles are used. But it would also be a good way of using thermocouples and PT100 sensors, allowing easy disconnection of the hot end while avoiding introducing temperature reading errors caused by the wiring.
Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod
Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod
Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
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Re: Thermocouples for Duet February 03, 2016 08:38AM |
Registered: 8 years ago Posts: 23 |
Hi again dc42, so I have connected the capacitor and using the appropriate firmware version. But still I am getting no response, can you upload a picture of the Duet expansion pin layout to double check my layout is correct? However I am sure the wiring is fine, is there anything else that might be wrong that I can check?
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Re: Thermocouples for Duet February 03, 2016 10:24AM |
Registered: 10 years ago Posts: 14,672 |
Sorry, my office is in the process of being packed up for my impending office move, so I've already dismantled my Duet+thermocouple setup. Please check that you using my 1.09r firmware release.
Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod
Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod
Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
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Re: Thermocouples for Duet February 03, 2016 03:41PM |
Registered: 8 years ago Posts: 31 |
I have ordered some bits from FArnell and will make up two circuits at the weekend.
Should be interesting and fun !
Regards,
Julian S.
T3DP3D Mini Kossel, E3D V6 hot end, 0.4mm nozzle, 200mm diameter Ali heated bed, Duet v0.8.5 & dc42 rep rap v1.18. DWC v1.15, PanelDue-7-1.16 DC42 IR Z Probe, 2 X MAX31855 &Thermocouples, PID heated enclosure, SolidWorks 2017, slic3r
Should be interesting and fun !
Regards,
Julian S.
T3DP3D Mini Kossel, E3D V6 hot end, 0.4mm nozzle, 200mm diameter Ali heated bed, Duet v0.8.5 & dc42 rep rap v1.18. DWC v1.15, PanelDue-7-1.16 DC42 IR Z Probe, 2 X MAX31855 &Thermocouples, PID heated enclosure, SolidWorks 2017, slic3r
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Re: Thermocouples for Duet February 03, 2016 05:11PM |
Registered: 10 years ago Posts: 14,672 |
Quote
JuJuDelta
I have ordered some bits from FArnell and will make up two circuits at the weekend.
Should be interesting and fun !
Good luck! Don't forget the 10nF capacitor. This is not shown on the schematic near the beginning of the datasheet, but is shown in the one nearer the end.
Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod
Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
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Re: Thermocouples for Duet February 06, 2016 11:51AM |
Registered: 8 years ago Posts: 31 |
Got it all working nicely, after an initial problem with /CS for the 2nd channel.
Soon found the problem with a scope and schematics for Duet.
Need to get some small bore ptfe heatshrink tubing to isolate my naked thermocouple tips
The PCB ended up being larger than I had hoped,due to poor vero board layout.
The PCB R/A thermocouple plugs/sockets are quite big too.
I can run off 3.3V or 5V, as there is a LDO 3.3V regulator fitted.
I was very careful to add a 10nF SMT resistor directly across the T+ T- pins of the MAX31855.
No noise problems.
I think there might be a typo in the RepRap page
[reprap.org]
NPCS1 is actually on pin 26 of the expansion connector, not pin 16
Currently:
CS (see below) NPCS0,NPCS1,TXD1,RXD1 27,16,11,12 20,11,6,7
Should be:
CS (see below) NPCS0,NPCS1,TXD1,RXD1 27,26,11,12 20,11,6,7
Edited 1 time(s). Last edit at 02/06/2016 12:31PM by JuJuDelta.
Soon found the problem with a scope and schematics for Duet.
Need to get some small bore ptfe heatshrink tubing to isolate my naked thermocouple tips
The PCB ended up being larger than I had hoped,due to poor vero board layout.
The PCB R/A thermocouple plugs/sockets are quite big too.
I can run off 3.3V or 5V, as there is a LDO 3.3V regulator fitted.
I was very careful to add a 10nF SMT resistor directly across the T+ T- pins of the MAX31855.
No noise problems.
I think there might be a typo in the RepRap page
[reprap.org]
NPCS1 is actually on pin 26 of the expansion connector, not pin 16
Currently:
CS (see below) NPCS0,NPCS1,TXD1,RXD1 27,16,11,12 20,11,6,7
Should be:
CS (see below) NPCS0,NPCS1,TXD1,RXD1 27,26,11,12 20,11,6,7
Edited 1 time(s). Last edit at 02/06/2016 12:31PM by JuJuDelta.
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Re: Thermocouples for Duet February 08, 2016 06:28AM |
Registered: 8 years ago Posts: 23 |
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Re: Thermocouples for Duet February 08, 2016 07:27AM |
Registered: 10 years ago Posts: 14,672 |
Please check that you are using a compatible thermocouple board as I described on the wiki page I referred you to earlier. If you are still using the E3D board, it may not be compatible with 3.3V electronics.
Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod
Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod
Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
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Re: Thermocouples for Duet February 08, 2016 07:51AM |
Registered: 8 years ago Posts: 23 |
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Re: Thermocouples for Duet February 08, 2016 12:59PM |
Registered: 10 years ago Posts: 14,672 |
That board should be compatible but you will have to add the 10nF ceramic capacitor to it.
Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod
Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod
Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
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Re: Thermocouples for Duet February 10, 2016 01:42PM |
Registered: 8 years ago Posts: 75 |
Hi dc42,
I think we're now at our wits end with this problem.
I'm working on the system described by HWrp156.
As specified above we are using the latest firmware (1.09) .
Have connected the thermocouple using the MAX31855K board and required capacitor.
Connected to port NPCS0. (pin 27).
The wiring has been quadruple checked.
config.g has been updated to read "M305 P1 X100".
When connecting via pronterface however the reading on the hotend is specified as -273.1. Which i assume is an error?
Because we have ordered multiples of the hardware parts (aiming for dual extrusion) we have swapped all hardware components to eliminate the possibility of faults in the hardware purchased.
I'm not sure really where to go from here, the addition of the high temp extruders is reliant on getting the thermocouples working.
Is there anything I can try or any form of troubleshooting method you can think of that will get us to narrow the problem?
Thanks,
I think we're now at our wits end with this problem.
I'm working on the system described by HWrp156.
As specified above we are using the latest firmware (1.09) .
Have connected the thermocouple using the MAX31855K board and required capacitor.
Connected to port NPCS0. (pin 27).
The wiring has been quadruple checked.
config.g has been updated to read "M305 P1 X100".
When connecting via pronterface however the reading on the hotend is specified as -273.1. Which i assume is an error?
Because we have ordered multiples of the hardware parts (aiming for dual extrusion) we have swapped all hardware components to eliminate the possibility of faults in the hardware purchased.
I'm not sure really where to go from here, the addition of the high temp extruders is reliant on getting the thermocouples working.
Is there anything I can try or any form of troubleshooting method you can think of that will get us to narrow the problem?
Thanks,
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Re: Thermocouples for Duet February 10, 2016 01:49PM |
Registered: 8 years ago Posts: 31 |
Do you have access to an oscilloscope or USBee analyzer ?
It will be very hard to debug if you can't see what SCLK, MISO and /CS are doing.
I have seen my second channel (nozzle) read 2000 occasionally on the web interface, not sure if it's a hardware or firmware problem yet.
Doesnt stop the print.
Regards,
Julian S.
T3DP3D Mini Kossel, E3D V6 hot end, 0.4mm nozzle, 200mm diameter Ali heated bed, Duet v0.8.5 & dc42 rep rap v1.18. DWC v1.15, PanelDue-7-1.16 DC42 IR Z Probe, 2 X MAX31855 &Thermocouples, PID heated enclosure, SolidWorks 2017, slic3r
It will be very hard to debug if you can't see what SCLK, MISO and /CS are doing.
I have seen my second channel (nozzle) read 2000 occasionally on the web interface, not sure if it's a hardware or firmware problem yet.
Doesnt stop the print.
Regards,
Julian S.
T3DP3D Mini Kossel, E3D V6 hot end, 0.4mm nozzle, 200mm diameter Ali heated bed, Duet v0.8.5 & dc42 rep rap v1.18. DWC v1.15, PanelDue-7-1.16 DC42 IR Z Probe, 2 X MAX31855 &Thermocouples, PID heated enclosure, SolidWorks 2017, slic3r
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Re: Thermocouples for Duet February 10, 2016 02:07PM |
Registered: 8 years ago Posts: 75 |
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Re: Thermocouples for Duet February 10, 2016 02:12PM |
Registered: 8 years ago Posts: 75 |
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Re: Thermocouples for Duet February 14, 2016 09:01AM |
Registered: 8 years ago Posts: 23 |
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Re: Thermocouples for Duet February 14, 2016 10:24AM |
Registered: 8 years ago Posts: 31 |
Hi, I am using exposed tip thermocouples which are not grounded.
As an experiment, When I connect the tip to 0V, it reads 2000'C
I will be insulating the nozzle thermocouple tip,with thin walled PTFE heatshrink tubing. If my nozzle heater cartridge fails, 12v might be applied to the nozzle metalwork and take out the max31855, or worse still, the arm chip on the duet pcb.
Regards,
Julian S.
T3DP3D Mini Kossel, E3D V6 hot end, 0.4mm nozzle, 200mm diameter Ali heated bed, Duet v0.8.5 & dc42 rep rap v1.18. DWC v1.15, PanelDue-7-1.16 DC42 IR Z Probe, 2 X MAX31855 &Thermocouples, PID heated enclosure, SolidWorks 2017, slic3r
As an experiment, When I connect the tip to 0V, it reads 2000'C
I will be insulating the nozzle thermocouple tip,with thin walled PTFE heatshrink tubing. If my nozzle heater cartridge fails, 12v might be applied to the nozzle metalwork and take out the max31855, or worse still, the arm chip on the duet pcb.
Regards,
Julian S.
T3DP3D Mini Kossel, E3D V6 hot end, 0.4mm nozzle, 200mm diameter Ali heated bed, Duet v0.8.5 & dc42 rep rap v1.18. DWC v1.15, PanelDue-7-1.16 DC42 IR Z Probe, 2 X MAX31855 &Thermocouples, PID heated enclosure, SolidWorks 2017, slic3r
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Re: Thermocouples for Duet February 14, 2016 04:35PM |
Registered: 10 years ago Posts: 14,672 |
Quote
HWrp156
Hi again dc42,
I have noticed that the thermocouple I am using is a grounded one and have read this may not be compatible with the MAX31855 chip? Is this the case and will this be why the board was not operating?
Thanks.
Have you read my wiki page on using thermocouples with the Duet? Your question is answered there.
Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod
Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
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Re: Thermocouples for Duet February 15, 2016 09:50AM |
Registered: 8 years ago Posts: 23 |
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