ST3Di Modelsmart 280 - Duet Maestro repair/upgrade

Veti · 6 Jan 2021, 11:40

@Blacksheep99 said in ST3Di Modelsmart 280 - Duet Maestro repair/upgrade:

to be clear, on the bed there are the power cables and then the thermistor cables right?

that is normally the case

Veti · 6 Jan 2021, 11:42

can you post a picture of the thermistor?

Blacksheep99 · 6 Jan 2021, 11:55

Blacksheep99 · 6 Jan 2021, 11:56

Each heater is 120x150mm

dc42 · 6 Jan 2021, 12:07

@Blacksheep99 said in ST3Di Modelsmart 280 - Duet Maestro repair/upgrade:

The probe\end stop has one but shared power circuits, the servo has a single feed to one pin with shared power, the hot ends have a single pin but share power also.

Shared +5V or +3.3v power and ground to the Z probe and the endstops is OK, if they use the same power voltage. Sharing power with the servo is also OK if they all need +5V power.

Shared +VIN power to two heaters is OK as long as the cable can handle the current for two heaters.

Blacksheep99 · 6 Jan 2021, 12:10

@dc42 said in ST3Di Modelsmart 280 - Duet Maestro repair/upgrade:

@Blacksheep99 said in ST3Di Modelsmart 280 - Duet Maestro repair/upgrade:

The probe\end stop has one but shared power circuits, the servo has a single feed to one pin with shared power, the hot ends have a single pin but share power also.

Shared +5V or +3.3v power and ground to the Z probe and the endstops is OK, if they use the same power voltage. Sharing power with the servo is also OK if they all need +5V power.

Shared +VIN power to two heaters is OK as long as the cable can handle the current for two heaters.

Thanks @dc42 I'll check the above. The two heaters are using the installed cabling so I should assume that it is up to the task. I am using the same PSU etc.

Blacksheep99 · 6 Jan 2021, 12:37

It has been mentioned in one of my other threads but worth me double checking. With my 24v psu I will need to change the fans on the printer to 24v also? the current ones are 12v. I think it's easier to replace than buy a converter?

jay_s_uk · 6 Jan 2021, 12:38

Either way to be honest.
My preference is to use the correct voltage fans but other people are happy with buck converters

Veti · 6 Jan 2021, 12:46

have you measured the resistance ?

Blacksheep99 · 6 Jan 2021, 13:41

@Veti said in ST3Di Modelsmart 280 - Duet Maestro repair/upgrade:

have you measured the resistance ?

169.1 Kohms If i read it correctly. That is at room temp which is cool today as there's no heating on at the moment in that room.

Veti · 6 Jan 2021, 13:42

modules:composer.user_said_in, @Blacksheep99, ST3Di Modelsmart 280 - Duet Maestro repair/upgrade

That is at room temp which is cool today as there's no heating on at the moment in that room.

which is about what temperature?

Blacksheep99 · 6 Jan 2021, 13:43

@Veti thermostat in that room says 12c

Blacksheep99 · 6 Jan 2021, 13:44

@jay_s_uk said in ST3Di Modelsmart 280 - Duet Maestro repair/upgrade:

Either way to be honest.
My preference is to use the correct voltage fans but other people are happy with buck converters

I think I side with you. I'll order some fans

Veti · 6 Jan 2021, 13:47

ok thats inline with a 100k ntc thermistor.

but which one is not as easy to determine.

can you put the thermistor at 100C using a known good temperature measuring tool?

i.e here is a beta 3950 resistance table.
https://www.keenovo.com/NTC-Thermistor-R-T-Table.pdf

Blacksheep99 · 6 Jan 2021, 13:55

@Veti said in ST3Di Modelsmart 280 - Duet Maestro repair/upgrade:

ok thats inline with a 100k ntc thermistor.

but which one is not as easy to determine.

can you put the thermistor at 100C using a known good temperature measuring tool?

i.e here is a beta 3950 resistance table.
https://www.keenovo.com/NTC-Thermistor-R-T-Table.pdf

I'm not sure how I'd go about that especially with what I have available at the moment. Am I daft thinking i could try suspend it in some boiling water and measure it then?