PT100 or Thermocouple K
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Hi,
I have both set of PT100 and Thermocouple K on my desk ready for use.
I the past I tested the ThermoC K but due to the interference problems I had at the time of test I gave up on it.My setup runs all cables in a cable chain, all my cables are unshielded at this point.
Since I have both PT100 and ThermoC K at hand I like to give it a new shoot…
PT100 & ThermoC K daughterboards are the original boards for Duet.
PT100 & ThermoC K cartridge original E3D (wire)Questions;
Pros and cons PT100 vs Thermocouple K?
What does each solution require to perform as exspected?
Do I need to change to shielded wires on all my cables or only for sensors..
Can I run a 28awg shielded two led wire to the thermocouple K and have that on a short led and still get accurate readings?
Can I move out the daughterboard to the extruder and run normal wires between the main board and the daughterboard and thus avoid interference?Thanks for reading
Roger -
With either sensor, if the cable chain also carries the wires for the extruder stepper drive, you will almost certainly need to shield the temperature sensor cable, or shield the extruder stepper motor cable.
If you use a thermocouple, you must run the twisted pair thermocouple wire right back to the daughter board. Therefore it is easier to use a PT100. You can use 2- or preferably 4-core shielded cable with a PT100.
If you remove the daughter board from the Duet, you must keep those wires short (I recommend more than 100mm) and away from sources of interference such as stepper motor cables.
If you have the old-style thermocouple board, you can add capacitors to it to increase the immunity to interference.
HTH David
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I run my PT100 cable through a tightly packed cable conduit with wiring for 2 fans, an endstop, heater cartridge, BLTouch and extruder stepper. To avoid interference I have twisted or braided as many of those cables as possible, and used four unshielded 20 awg wires for the PT100, also twisted. So far no issues with temperature readings.
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Thanks for the replies, seems like PT100 four wire is the prefered choice among you.
What would be the argument to run a Thermocouple K over a PT100, Im asking because Duet offers both and if PT100 if prefered whats the argument for Thermocouple K?I just what to learn the pros & cons…
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Thermocouples are good for very high temperatures. See https://duet3d.dozuki.com/Wiki/Temperature_sensors.
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i found 3-wire PT-100 sensors. how do i connect it to 4 wire PT-100 board?
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You can connect the two wires that are connected to one end of the element as for a 4-wire sensor, and the single wire that is connected to the other end as for a 2-wire sensor. This isn't ideal, but it will work.
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In your blog post - https://miscsolutions.wordpress.com/2016/06/25/more-delta-printer-upgrades-wifi-and-silence/
You mention splitting the 2 wire PT100 to a 4 wire, is there any point to that?
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In your blog post - https://miscsolutions.wordpress.com/2016/06/25/more-delta-printer-upgrades-wifi-and-silence/
You mention splitting the 2 wire PT100 to a 4 wire, is there any point to that?
http://www.pentronic.se/media/26460/The_effect_of_2_3_4_wires_on_Pt100_060210.pdf
Because math?
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In your blog post - https://miscsolutions.wordpress.com/2016/06/25/more-delta-printer-upgrades-wifi-and-silence/
You mention splitting the 2 wire PT100 to a 4 wire, is there any point to that?
http://www.pentronic.se/media/26460/The_effect_of_2_3_4_wires_on_Pt100_060210.pdf
Because math?
Interesting, not super familiar with how they worked so when you 'just add' another wire to something it usually doesn't add functionality. So can you do the 2-4 conversion in the smart effector itself? Since the connector is 2 pins on the underside, or is that not built into the effector(I ask because my smart effector only has a 2 pin input but has the full 8(4 for PT100) on the top)
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Yes we do the 2 to 4 wire conversion in the Smart Effector itself. So the resistance of the wires and connectors between the Smart Effector and the Duet get cancelled out if you use 4 wires between the effector and the daughter board on the Duet; but the resistance of the wires from the PT100 to the 2-pin plug and the resistance of the 2-pin connector itself don't get cancelled.
If you ever use a 4-wire PT100 you can:
1. Desolder the 2-pin connector from the Smart Effector and replace it with a 4-pin in-line Molex Microfit 3 connector (the PCB is designed to accept both);
2. Cut the two traces on the top of the PCB. They are designed to be cuttable using a 3mm drill, stripboard style.
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Alright so if I want to just do that later I can go ahead and wire the 4 cables from the board to daughter and just upgrade the 2 pin to 4pin later?
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Alright so if I want to just do that later I can go ahead and wire the 4 cables from the board to daughter and just upgrade the 2 pin to 4pin later?
Yes.
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Alright so if I want to just do that later I can go ahead and wire the 4 cables from the board to daughter and just upgrade the 2 pin to 4pin later?
Yes.
If I wire 4 from effector to daughter(but only 2 from PT100 to effector) do I leave the jumpers installed or remove them(and software support for it as well)?
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Remove the daughter board jumpers.
