reef-pi has suddenly stopped recording ph data (Robotank)

[kdx7214]

I've been running reef-pi on a RoboTank for quite some time now and it's always worked perfectly. Last both the pH and one of 3 temperature probes stopped recording data. I've downloaded and run @robsworld78 g++ script and it reads the sensor quite well and shows values in the range I would expect. The temperature probe probably failed and I've ordered new ones (that Rob recommended) but I had 2 extras so no worries.

I just can't seem to figure out why ph data would stop recording and showing up on the dashboard. Any ideas of what to check?

 

[Sral]

can’t say I have experience with your specific problem, but have you tried turning it off and on again ?
I would try the following order:
- reload ReefPi
- reboot the Pi
- disable the pH entry in the pH tab, reload ReefPi and re-enable the pH
- delete the pH sensor in the pH tab and create a new one
- delete both the ph entry in the pH tab and driver, reload ReefPi and create them anew

Afterwards you‘ll also need to reset the dashboard graphic to the new sensor.

 

[kdx7214]

can’t say I have experience with your specific problem, but have you tried turning it off and on again ?
I would try the following order:
- reload ReefPi
- reboot the Pi
- disable the pH entry in the pH tab, reload ReefPi and re-enable the pH
- delete the pH sensor in the pH tab and create a new one
- delete both the ph entry in the pH tab and driver, reload ReefPi and create them anew

Afterwards you‘ll also need to reset the dashboard graphic to the new sensor.

Oops, I forgot to mention that. I've done a reload, reboot, and power off/on cycle and still no go. Not sure but it might be a data corruption or something.

 

[ColoredRock]

you can try this

reef pi reset database

Can I wipe the data history from my reef pi - currently just set up on a breadboard for testing with temp sesors and timers. I'd like to wipe the cached historic data so that the dashbaord resets and only shows new data, how can I do this? thanks

www.reef2reef.com

 

[kdx7214]

you can try this

reef pi reset database

Can I wipe the data history from my reef pi - currently just set up on a breadboard for testing with temp sesors and timers. I'd like to wipe the cached historic data so that the dashbaord resets and only shows new data, how can I do this? thanks

www.reef2reef.com

Somehow it randomly started working again without anything else on my part. I wish I knew why it did it, but I'll count it a win

 

[Ranjib]

When it stopped working, please check the logs for details. If there’s an error, you should see that in log(as well as Ui). If it’s disabled or other not reading probes for some other reason, that too will be clear from the log.

 

[kdx7214]

When it stopped working, please check the logs for details. If there’s an error, you should see that in log(as well as Ui). If it’s disabled or other not reading probes for some other reason, that too will be clear from the log.

Sorry about this, but it randomly started working again. I'm not even sure where the log files are for it. Are they accessible from the website interface?

 

[MichaelA18454]

I also have just started having the same issue with the DS18B20 temperature sensor stop working after a short period. These sensors have provided trouble free service for 4 ~ 5 years. I also thought the sensor needed changing, but again after a brief period of disconnection they start to function again. So far I have had to change out the sensors every other day.

Since the Pi-Zero's are back available again, I purchased another thinking the Pi may have been damaged, but is was fine and so I built up the spare as a test board.

The question about wet or dry, mine has been wet for a long time without issues, but now I will leave the test board ON and see if the same thing occurs with the sensor dry.

error log shows

"temperature sub-system. Failed to read sensor 8 - Heater. Errorpen /sys/bus/w1/devices/28-d9b9151e64ff/w1_slave: no such file or directory"

The sensor connections have not changed with 3V3, a 4K7 resistor to Signal & Ground.

I am running Version 6.0, but the same thing was happening with Version 5.2, so I would be surprised if it be a software issue.

Cheers

 

[Sral]

I also have just started having the same issue with the DS18B20 temperature sensor stop working after a short period. These sensors have provided trouble free service for 4 ~ 5 years. I also thought the sensor needed changing, but again after a brief period of disconnection they start to function again. So far I have had to change out the sensors every other day.

Since the Pi-Zero's are back available again, I purchased another thinking the Pi may have been damaged, but is was fine and so I built up the spare as a test board.

The question about wet or dry, mine has been wet for a long time without issues, but now I will leave the test board ON and see if the same thing occurs with the sensor dry.

error log shows

"temperature sub-system. Failed to read sensor 8 - Heater. Errorpen /sys/bus/w1/devices/28-d9b9151e64ff/w1_slave: no such file or directory"

The sensor connections have not changed with 3V3, a 4K7 resistor to Signal & Ground.

I am running Version 6.0, but the same thing was happening with Version 5.2, so I would be surprised if it be a software issue.

Cheers

I‘d recommend starting a dedicated thread.

Nevertheless, that error shows that the system failed to communicate with the sensor, if it was working before it’s likely an electrical error disturbing signal integrity. Might be outside or inside interference, might be wet or corroded contacts, might be a lot of things.

I’m currently working on a different project reading „DS18B20“ sensors , I think @theatrus just mentioned that they are quite often not original and can show slightly unexpected behavior, and when I handle the just 150 mm short cables I often get read values of -1000, e.g. a communication error. When I resample the sensor a maximum of 10 times after these errors, I mostly eradicated the issue, although I’m working with a Pi Pico microcontroller and the library there works probably slightly different.

I would try if a smaller pull-up resistor solves the issue, like a 2.7k for example. You can also try two 4.7k in parallel, should result in the same pull-up strength.

 

[MichaelA18454]

Thanks again, Sral.
Appologies. Why the suggestion of starting a new thread?
I read through this and thought the subject was appropriate!

Anyways, I reduced the Pullup resistor to 3K6 but without change.
The sensors I have are from old stock purchased many years ago, and have not experienced this before. I bought another 10 sensors in the past month and they didn't resolve the issue.
I reviewed the data sheet and it states VCC to be 3V3 to 5V5 and I use 3V3 as per the instructions. Regardless, I find this bizzarre that it all of a sudden I am seeing the issue persist.
There has to be a reason.

 

[Sral]

Thanks again, Sral.
Appologies. Why the suggestion of starting a new thread?
I read through this and thought the subject was appropriate!

Anyways, I reduced the Pullup resistor to 3K6 but without change.
The sensors I have are from old stock purchased many years ago, and have not experienced this before. I bought another 10 sensors in the past month and they didn't resolve the issue.
I reviewed the data sheet and it states VCC to be 3V3 to 5V5 and I use 3V3 as per the instructions. Regardless, I find this bizzarre that it all of a sudden I am seeing the issue persist.
There has to be a reason.

Mostly because the thread was more concerned with the pH probe, which is I2C, uses a different driver and uses a different system in ReefPi. If you still think it appropriate, maybe I’m overthinking it (again). Wouldn’t be the first time and definitely won’t be the last

Anyways, on the topic:
3k6 might not be enough, but then again, this might not be the solution either. I’m currently running 1k6 on my Pico setup with 3V3, but also couldn’t tell you if there would even be a difference to 3k2 or even larger. Cable lengths are important as well.

Although reading you say that completely new sensors (with new cable as well ?) behave the same, I‘m somewhat suspecting a software problem or hardware issue between PI Zero and the plug and everything in between (including the pull-up, although we might rule that out if you tried a different one).

How is the second Pi progressing ?
Do you have another system available for testing, like a Pi Pico, Arduino or ESP32 ?

 

[MichaelA18454]

I started a new thread as you suggested, Thanks Sral

I am not thinking the 4K7 resistor is the issue because the Pi-Zero (V.5.2) has been running for 4 ~ 5 years without issue using 4K7 pull-up, but your comment on cable length has merit .

When the issue started, I had soldered joints for the cable extension, and found the extension cable was plain copper and had become oxidised black and was not solderable any more. So I changed the extension cable out for a screened sheath with a larger cross section tinned copper cores, and changed to the 3.5mm stereo jacks, and now I think back, the issue occurred more often. I also changed out the Pi-Zero to a new one loaded with Version 6.0.

As for the second Pi-Zero?

It is the Pi-Zero (Version 5.2) that had been running for all those years without issue,
I changed it out for a new Pi-Zero (Version 6.0).
It is still running after 3 weeks, the test does not include the extension!!!

So my take away is, your comment of electrical noise and cable impedance needs to be addressed. I will terminate the screen to ground at the Pi and add a 100N cap to the SIG - GND and see how that goes, and get back to you.

Much appreciate your support.