Timeline for Oxygen sensor voltage changes when machine is powered on. Interference?
Current License: CC BY-SA 4.0
7 events
| when toggle format | what | by | license | comment | |
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| Sep 3, 2021 at 8:11 | comment | added | Spehro 'speff' Pefhany | Yes, I did not change the circuit from a purely theoretical point of view, but if you draw arrows where current flows (relay coil current in particular) and consider the wires as having some resistance, I think you will see what I mean. | |
| Sep 2, 2021 at 7:19 | comment | added | Daniel Dowling | Like, should I ground it with a 100k ohm resistor? would that reduce noise coming in from the ground rail? | |
| Sep 2, 2021 at 7:08 | comment | added | Daniel Dowling | Forgive my ignorance, but aren't your changes functionally identical to what was there before? As I said, I moved the relay to the other side of the breadboard, so it is now connected directly to the ground rail. Essentially the rest of the circuit is as you showed it. I can add the noise filter, but that's not going to fix a DC offset, right? | |
| Sep 2, 2021 at 7:01 | comment | added | Daniel Dowling | I'm confused. Should I leave pin 2 connected to ground? Oh, sorry, I see now. I misread your post. | |
| Sep 1, 2021 at 4:13 | comment | added | Spehro 'speff' Pefhany | I did not suggest floating it- that won't work- there needs to be a DC path for the in-amp bias currents. I suggested wiring pin 2 and pin 3 directly to the sensor inputs. Pin 2 is still grounded but there is no current flowing through the wire such that it will appear in series with the sensor mV. | |
| Sep 1, 2021 at 4:11 | comment | added | Daniel Dowling | Thank you so much for your response. I will try it. The reading from the oxygen sensor is definitely not the problem. I am getting plausible values from the sensor when the machine is powered off. Also the device will always be operating at atmospheric pressure, so that's not an issue either. As for the wiring, I actually moved the relay to the other side of the board to see if that helped, but S- is still grounded so I will try floating it as you suggested. | |
| Sep 1, 2021 at 3:59 | history | answered | Spehro 'speff' Pefhany | CC BY-SA 4.0 |