UM1 electronics 1.5.7 Temp 4?

[jonnybischof 60]

Does anyone know what the fourth "temperature sensor" on the UMO electronics shield 1.5.7 is for?

On the schematics, next to the Temperature sensors 1-3, there is another resistor divider (R3, R13, 100K and 4.7K), which make up a pseudo-sensor with a fixed 100K resistor instead of an NTC.

It's connected to 19V "VCC/2" instead of the 5V "VCC" (from the Arduino). It looks like a "19V presence detect"...

Do these need to be there, or not?

 

[anon4321 16]

As near as I can tell, this isn't mapped in Marlin but I'm not 100% sure...

 

[anon4321 16]

Actually being able to measure the Vin is handy. Throw in a current sensors resistor so we can get amps and power too.

I'm not sure the ratio is good. Seems like it would only provide about an .85 V input which sounds low.

 

[anon4321 16]

I don't think it was a TEMP4. Even the original version only had 3 temp inputs:

http://reprap.org/wiki/Ultimaker%27s_v1.0_PCB

 

[jonnybischof 60]

It doesn't have anything to do with temperature measurement - but it's the same thing in the same place so I thought I'd call it that

Actually, knowing the precise value of VIN is not that important - the only parts that directly use that voltage are the motors and heaters. Bot work well over a "wide" voltage range.

It might be useful for the electronics to be able to sense whether the power is present or not, because there could also be only USB power which makes the electronics work, but not the motors and heaters. But afaik that feature isn't used, because there is no error message when you try to make the printer work without external power (other than USB).

Anyways, I'll toss it from my Arduino shield (see http://umforum.ultimaker.com/index.php?/topic/9332-new-part-day-silent-stepper-motors/?p=95630) because it makes no sense.