I use a PT100 on my main printer, and I have just gotten a PT1000 (no amplifier board needed).

While a thermocouple might have faster temperature response, I like the PT100 and it is definitely not prone to breakage on a printer.

PT100 is calibrated to have 100 Ohms at 0 C, while a thermocouple has to be calibrated (think ice bath) against another already calibrated thermocouple - however it wouldn't hurt to confirm resistance on a PT100 either.

Thermocouples are prone to noise because the signal is a voltage signal and can change quickly.

An RTD (like PT100) can be affected by the length of wire because it can subtly increase resistance (hence why I want to try a PT1000 - precision piezo sells some) - although if they came with four wires you could actually compensate for the resistance - but alas they do not for printers.

So I have read that ATX style power supplies can be turned off by the RRF. Is it possible to wire an industrial power supply that must be turned on normally, but is latched in such a way that a signal could come from the duet board to turn off the power (thus release the latch).

I know there are power relays that might be applicable, but I don't think a regular switch would be appropriate with this setup.

How is this any different from regular cartesian movement?

Update:

It just worked after I redid the entire wiring and seating and got:

Auto tuning heater 1 completed after 3 idle and 10 tuning cycles in 731 seconds. This heater needs the following M307 command:
M307 H1 R1.701 C224.5:193.5 D8.77 S1.00 V12.8

Quite different than the original.

Something rather interesting happened yesterday. When I went to do another test it heated up to target temperature and then cooled down naturally. The test never completed and I couldn't get the heater to heat up again.

So now, I try to heat it up and have a fault. I reset it, and jiggle the wires a bit as I tell it to heat again. It does so.

I do not know if these are related but will be taking a closer view at the wires of the heater. The printer has been sitting for some time and went through a house move.

Here is the output of the console (backwards in time):

1/17/2021, 2:12:31 AM	Warning: Auto tune of heater 1 failed due to bad curve fit (R=1.548, 1/C=0.0056:0.0050, D=9.3)
1/17/2021, 2:08:05 AM	Auto tune starting phase 3, fan on
1/17/2021, 2:04:42 AM	Auto tune starting phase 3, fan off
1/17/2021, 2:01:44 AM	Auto tune starting phase 2, heater settling
1/17/2021, 1:58:17 AM	Auto tune starting phase 1, heater on
1/17/2021, 1:58:12 AM	M303 T0 S215
Auto tuning heater 1 using target temperature 215.0°C and         

PWM 1.00 - do not leave printer unattended

The previous model from well over six months ago, but updated by an M500 command:

M307 H1 R2.044 C129.200:129.200 D5.70 S1.00 V12.8 B0

I haven't attempted to do it again because it is getting late, and just wanted some feedback if this is something that might change by running it again.

It is not the negative deadtime another search for this issue had.

The printer is a delta printer, duet wifi (early version), V6 connected to a Smart Effector, PT1000 sensor.

Smart effector

I believe it was 9 factors using 10 points or something like that (it was done with the configuration tool).

I have been using it for a while, and it always seems to work. My main concern was if the math could provide issues because of the imprecision.

Just a small question:

If I were using sensorless homing from a duet wifi (which I am), along with a 10 point calibration before every print are there any sorts of problems I should expect to come up?

It is using smart effector.

I am considering adding "real" endstops such as optical (I have a few).

I printed a few circles on my delta's build platform using a layer height of 0.2mm.

Image of it is here with annotations as to what they feel like, and the height map:

https://imgur.com/a/eFfAAAC

Printer equipment is a mini kossel with linear rails, smart effector, v6, 600mm bowden tube, bondtech extruder. PEI bed.

So I have done everything that I know I can do - namely delta autocalibration, and mesh compensation.

The center is looking perfect, and a couple of them are okay as well. But some are rough (the lines themselves) and some have actual raised bits on them. I am considering lowering the extrusion rate to see if some of that goes away.

Any other suggestions?

I cannot say that it is perfectly calibrated, but I have s3d and prusaslicer producing reasonably good models on some basic calibrations. So this might be sufficient.

I have finally gotten some results with acceleration of 3000, and jerk of 400.

Any higher of a jerk and it makes too much noise, 400 still has some noise but it is almost reasonable.

In my test I had the corners progressively get worse, and finally the Z seam.

At no point did the Z seam reduce amount.

I figure a good value is roughly in the 0.5 to 0.8 range, and I am testing that now. The documentation seems to suggest 0.5 is a reasonable place to be, which looks right. Although it is questionable if there will be a way to really see much difference here.

I am also looking for other strategies to reduce the z seam as well.