Resistor Heating Up

[deadpickle]

I am converting from probe to tap so my MCU side has a bat85 still attached. I have wired up the optical sensor side as the diagram suggests with a 220 ohm resistor soldered to the red with the white connected to the top of the resistor, as well as the green and black connected. When I start up the machine the resistors gets very hot. I'm not sure what I have done wrong and could use some advice

 

[kyleisah]

Green and red are not supposed to be connected.

Please look at the optical sensor diagram very closely

https://media.discordapp.net/attachments/933426436897919016/1153422703496278036/unknown.png

 

[kyleisah]

It is also only supposed to receive 5V

 

[vinnycordeiro]

Looking at the manual right now, just to double check:

• white wire connected to 5V
• 220R resistor connected to 5V, the other lead connected to the anode pin (red)
• black and green wires connected to GND

The manual, as is in the repository, is clearly dubious. Better to open an issue for that. Also, it's possible that you killed the sensor.

 

[deadpickle]

I miss typed, sorry. Editing the post. Green is connected to black.

 

[deadpickle]

Looked into the setup a bit more:
On MCU the red is connected to 12/24V, blue to ground, and the bat85 is slotted into PG4 (not ground).
With that on the MCU side should the sensor side be:
Red/white with resistor to red (MCU), black/green to PG4 and blue to blue(MCU)

 

[claudermilk]

Follow the manual diagram. At one point I had to wire up a sensor and it worked fine, though I didn't feel the resistor for heat.

Red/white spliced, with the resistor on red before the white splice. That goes to 5V on the controller.
Blue to signal on the controller.
Green/black spliced and to ground on the controller.

The main thing is it's 5V. Not 12V or 24V.

 

[deadpickle]

So if my controller has 12/24V (FAN3) and the OPB991T51Z sensor requires 5 volts does that mean I need a different resistor than the 220 Ohm in the diagram?

I tried again and the sensor is not heating up but it does just say "triggered" on the ZEnd and probe.

 

[claudermilk]

The sensor needs 5V. If you fed it 12/24V it may be fried. What controller do you have? There must be some port that can send 5V.

 

[deadpickle]

The sensor needs 5V. If you fed it 12/24V it may be fried. What controller do you have? There must be some port that can send 5V.

The pin out is linked as FAN3. The board is an SKR 2. Does the optical sensor need a constant feed like the induction probe did? If not then one of the end stops might work, I'm not sure

 

[claudermilk]

I believe it does. I have an Octopus and the 5-24V Tap PCB, so it's connected exactly like the inductive sensor was. Can you set that FAN3 to 5V?

 

[deadpickle]

I believe it does. I have an Octopus and the 5-24V Tap PCB, so it's connected exactly like the inductive sensor was. Can you set that FAN3 to 5V?

I don't think I can, there's no jumper associated with fan3 I purchased a 5/24v Optotap so hopefully that will get things going