PT100 with amp board  

RE: PT100 with amp board

You will find the biggest difference is if you use an enclosure.

The e3d will start to have trouble if the ambient temperature climbs over 40 Deg C whilst the mosquito allegedly can handle much higher temperatures since the heat break is much more efficient at cooling, this will obviously also depend on what filament you are using.

Just for information I read they are also developing a water cooled version!.

RE: PT100 with amp board

Posted by: chocki

You will find the biggest difference is if you use an enclosure.

The e3d will start to have trouble if the ambient temperature climbs over 40 Deg C whilst the mosquito allegedly can handle much higher temperatures since the heat break is much more efficient at cooling, this will obviously also depend on what filament you are using.

Just for information I read they are also developing a water cooled version!.

OMG! I may wait for a watercooled version then!

Right now I have a Sunon upgrade on my extruder, but it causes drafts in my enclosure on certain parts and thought about water cooling my e3d, but it just seems like too much work with the Bondtech BMG upgrade. 

RE: PT100 with amp board

Just wait for the Bunny Science laser assisted heating extruder. Even better localized heating than isolating the heat block.

Bunny Scientists and Bear are running for their lives in logo for good reason.

RE: PT100 with amp board

And that's no kidding, MIT already built one and published an article with results:

RE: PT100 with amp board

Do you get free ear plugs with that?

But wow, 282 cm³/hr

RE: PT100 with amp board

Do you get earplugs with that?

No. You print yours.

RE: PT100 with amp board

I think I'll just use this | whilst watching bunnies and bears running to the hills 😜 , never mind the earplugs.

                                       V

https://www.prusaprinters.org/prints/3467-diy-bar-cocktail-machine

RE: PT100 with amp board

Posted by: dobbewan

Correct. Like I mentioned, there was a very detailed thread on this when it was first added to the firmware in the mk2 hayday. I would give credit to those involved in importing the tempature tables, but for whatever reason since the new forum format, it is gone.

Forgive me, but yes that thermistor pin does matter. In my picture I have it on the right thermistor pin. Lately I have been traveling, so I unfortunately don't have my printer or notes with me. My goof. 

As far as accuracy... 

It is very accurate actually. In the old thread that I can't find, they actually test them side by side with a thermistor. The only issue I have is colder tempatures. Anything below 200c it seems to bounce around... But it could be due to the 60w overkill heater I have. I was having crazy variences for a bit, but found out the stock molex plug was the culprit and replaced with a xt-30.

 

Just to clarify - the only thing you did was wire directly to the thermistor input, (and + & - to the MMU header) and uncomment the line spec'ing the PT100? 

You made no changes to the Temp Tables?

RE: PT100 with amp board

UPDATE:  I dug through the code again, and it turns out that when you uncomment "E3D_PT100_EXTRUDER_WITH_AMP" it automatically factors in the 4k7 resistor.

Problem SOLVED.

RE: PT100 with amp board

OT, but not exactly smooth sailing going to a Mosquito here. The thermal transfer rate is significantly worse and it has been very sensitive to parts cooling airflow. I'm creating a silicone sock for mine to try getting the mosquito to match the performance of my regular E3DV6 (not even gold).

At the very least, I would keep your old setup ready to to swap back if the mosquito does not work out.

RE: PT100 with amp board

Okay, so I ordered the PT100 w/ amp. I downloaded the v3.73 firmware and uncommented PT100 w/ amp line in the variant for the MK3s (my printer). Based off this thread I created an image showing where I think you are supposed to plug in the amp wires (if someone could double check this it would be much appreciated). My understanding is that since I am using the same thermistor pin I don't have to change anything with pin assignment in the firmware, is this correct? I should be able to compile my uncommented PT100 line firmware, flash it, and should be good?

RE: PT100 with amp board

Oops the image quality on that last post wasn't very good, here it is in higher resolution.

RE: PT100 with amp board

Can't say anything about correctness of your wiring plan without knowing the cabling color scheme

Purple

Blue

Orange

Which is connected to VCC, GND and signal out of of amp on your harness?

If your harness and scheme are correct then you should be able to verify that

purple = signal out

blue = vcc (+)

orange = gnd

We can't know anything is right or wrong without info on which color wire goes where on the amplifier end.

RE: PT100 with amp board

So, yes you have the correct pins on the EINSY end, but that color scheme would be correct if and only if the amplifier end is wired like...

It's a totally bizarre choice of colors and we have no indication of how your wiring harness is actually put together. The header on amplifier end is also prone to being plugged in backwards which would reverse power the amp and likely destroy it.

RE: PT100 with amp board

Thanks for the help! I will check the color scheme (and update my graphic) when I get the kit which is supposed to come today. This may be a dumb question but what is the header on the amplifier end? Are you saying the connnector on the board that goes from the PT100 to the amp board is often plugged in backwards?

Also I'm still hoping to verify that the only thing I need to modify on the firmware is to uncomment the PT100 w/ amp line. If there are pin assignment changes needed then any help with that would be appreciated.

RE: PT100 with amp board

By "header" I mean the row of three metallic connector pins that are all bent at right angle to accept a cable connector.

That three pin header is on one end of the amplifier board. That is the header onto which your cable to EINSY will connnect.

----

No pin reassignments in the firmware to make.

Just uncomment 

#define E3D_PT100_EXTRUDER_WITH_AMP

RE: PT100 with amp board

Awesome, now I should be set. Thanks for clarifying the "header" I will take special note of that connection orientation. 

RE: PT100 with amp board

Well, I've gone and ordered my e3d PT100 sensor and amp, a titanium heatbreak, and a nickel plated copper heatblock.

My Printer is in pieces whilst I replace the PSU with a meanwell lrs-350-24, and a reverse einsy case. I have also fitted heatsinks to both rear and fronts of the trinamics drivers, and the rears of the heater FETS.

I have also ordered a new 40W heater from E3d which has a molex connector on it, and the PT100 wiring also comes with a connector, this will allow me to remove the hot end without having to unwrap all the cabling.

Hopefully I may get everything finished by next week, I wasn't happy with the existing GT2 pulleys on X and Y as one of them were off centre!, so have replaced with two as recommended by Guy2K, and also have my 0.9 OMC motors to fit to the X and Y axis.

Poor printer looks in a right state with cables hanging off everywhere 🙂 but I have to work as well and eat and sleep. There's not enough hours in a day!!!

Quite a bit of work including modding amp board and thermistor input circuit (Remove 4k7 resistor), but on Therm1 as this is not used, then swap TEMP_0_PIN and TEMP_1_PIN in the firmware, recalculate the thermistor tables and see how I get on.

This also depends on how my hydrocortizone injection into my shoulder goes in a few days, as I may not be able to move my arm!.

And if SWMBO will allow me time since she always seems to have something else for me to do...

RE: PT100 with amp board

Remove 4k7 resistor

I think we discovered later in this thread that the resistor does not have to be removed because one of the PT100 thermistor tables has values that already account for the resistor's presence.

RE: PT100 with amp board

True, but the resolution is poor. The ATMEGA 2560 only has a 10 bit ADC input so that's 1024 values between 0v and 5v.

If we use the amp as is it can only swing  1 Deg C Vout = 1.110909    and say  410 Deg C Vout = 2.692565      a difference of 1.581656 V.

This only gives us a resolution of 324 values, or less than the Deg values between 410 and 0, and the 4k7 pullup resistor just offsets everything and does not allow an increase in gain from the amp.

If I decide to remove the resistor, I can increase the gain of the amp from 10 to 16

1 Deg C Vout = 1.774411            410 Deg C Vout = 4.300728      a difference of 2.526317 V

This would give a theoretical maximum readable value of 539 Deg C, Way hotter than we print at.

But now we use 517 values over the range of 410 degrees, much better resolution.

Most likely since I have a Mk3 I will just use the unused analog input (PK0) in connector P3 and mod the amp board and alter the lookup table for temperatures, sounds a lot easier.