Weird display of temperature with reef-pi

kdx7214 · Jun 16, 2022

I have 2 temperature probes connected to the system (using a Robo Tank controller). One of them (labeled Sump) is working just fine. The other one (labeled Display Tank) has worked fine until this morning. Suddenly it's display is weird. When I look at it under the Temperatures tab one graph is off and one is normal. What the heck is going on?

robsworld78 · Jun 16, 2022

kdx7214 said:
I have 2 temperature probes connected to the system (using a Robo Tank controller). One of them (labeled Sump) is working just fine. The other one (labeled Display Tank) has worked fine until this morning. Suddenly it's display is weird. When I look at it under the Temperatures tab one graph is off and one is normal. What the heck is going on?

That's likely the sensor going bad, -1 is a common reading when that happens, might need another sensor. I believe it's only showing the error on the chart that's updated every read, the other chart has averages or skips some readings to show a larger time frame.

Sral · Jun 17, 2022

Funny coincidence: same was discussed a few days ago after this comment in the main thread.

Seems that the sensors are not made well enough and the wires/contacts corrode slowly.

kdx7214 · Jun 17, 2022

robsworld78 said:
That's likely the sensor going bad, -1 is a common reading when that happens, might need another sensor. I believe it's only showing the error on the chart that's updated every read, the other chart has averages or skips some readings to show a larger time frame.

Hmm. The odd part is that when I mouse over the readings all of them look correct. I'll swap out the heater though and see if that helps. Thanks!

Update: I just changed the sensor out about 10 minutes ago and it's still showing all readings correct, but the graph is wrong. Did I get a second bad sensor?

kdx7214 · Jun 17, 2022

I have now tried 3 sensors and all of them are giving the same results. @Ranjib do you have any idea why this would be happening? The only issue seems to be the graph. Below is the updated pic. You can see the -1 readings where I changed sensors and yet the graph is still hokey. The second pic shows a mouseover of one of the readings where it's correct, but the graph is messed up.

robsworld78 · Jun 18, 2022

Hopefully you didn't get another bad sensor. Some think there's a lot of flaky counterfeit sensors that are prone to noise and moisture can get in the end tube. I've had a sensor that always gave errors when submersed but out of water it was ok. I've had a few people have bad luck with them and got these one, they solved the problem every time.

2 PCS/LOT DS18B20 High Temp Sensor 3 meters Waterproof Thermometer Sensor -55 ~125 Celsius Degree Thermometer Probe

It is a 3 meters Thermometer Sensor/Temperature Sensor, Type : DS18B20 high temp sensor,Silicone shielded Cable, Measurement range : -55°c to 125°c (-67℉ to 257℉), Power Supply Range: 3.0V~5.5V, Suitable for Thermometer/Digital Thermostat etc.Parameters: Type : DS18B20 high temp sensor,Si

www.droking.com

Ranjib · Jun 20, 2022

kdx7214 said:
I have now tried 3 sensors and all of them are giving the same results. @Ranjib do you have any idea why this would be happening? The only issue seems to be the graph. Below is the updated pic. You can see the -1 readings where I changed sensors and yet the graph is still hokey. The second pic shows a mouseover of one of the readings where it's correct, but the graph is messed up.

can you show us the configuration for each sensor ? just want to make sure you are using different probes

kdx7214 · Jun 20, 2022

Ranjib said:
can you show us the configuration for each sensor ? just want to make sure you are using different probes

Sure, here you go.

FYI, I decided to try something weird. I reformatted the Pi and reinstalled everything, then set it back up. I couldn't figure out how to wipe the data that was stored, so that was easier lol. Once I did this and set it up as shown in the images it worked okay.

robsworld78 · Jun 20, 2022

kdx7214 said:
Sure, here you go.

FYI, I decided to try something weird. I reformatted the Pi and reinstalled everything, then set it back up. I couldn't figure out how to wipe the data that was stored, so that was easier lol. Once I did this and set it up as shown in the images it worked okay.

The sensor ID in both those images are the same which would suggest they are showing output from the same sensor.

kdx7214 · Jun 20, 2022

robsworld78 said:
The sensor ID in both those images are the same which would suggest they are showing output from the same sensor.

Wow, somehow I completely missed that. I've got that fixed now. Still, the wipe/reinstall did fix the graph

Ranjib · Jun 25, 2022

kdx7214 said:
Wow, somehow I completely missed that. I've got that fixed now. Still, the wipe/reinstall did fix the graph

Yay..I was exactly suspecting this. Happens to most of us. Glad you got this sorted

kdx7214 · Jun 25, 2022

Ranjib said:
Yay..I was exactly suspecting this. Happens to most of us. Glad you got this sorted

I am as well. There's still something not right about the graphing code. I shouldn't have had to wipe the data to fix it when actual data points were present. Overall though, I'm really happy with reef-pi. Freaking amazing job on it! Keep up the great work @Ranjib !