Help with pH board.

[im_jeremy5]

Hello,

  I need some help with a robo-tank pH board i just purchased. I have a brs probe. I built my own reef-pi that is running on reef-pi 5.1.

  The board gets a continuous 5v. The jumper is on the 5v selection. I set it up following the steps in the reef-pi manual using the ph-EZO driver and the decimal address sent with the phBoard (98). (It also said the hex address is 0x62). i2c is enabled in raspi-config. This is the only i2c device connected. The green light is on on the board.

  Reef-pi doesn't seem to recognize the device. I don't get any reading, nothing happens when I click calibrate.

  This is the error in reef-pi:
   "ph subsystem: Failed read probe:pHError:write /dev/i2c-1: remote I/O error"

  i2cdetect returns:
pi@raspberrypi:~ $ sudo i2cdetect -y 1                        0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:          -- -- -- -- -- -- -- -- -- -- -- -- --

10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --

20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --

30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --

40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --

50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --

60: -- -- -- 63 -- -- -- -- -- -- -- -- -- -- -- --

70: -- -- -- -- -- -- -- --                       
pi@raspberrypi:~





   Not sure I understand this exactly, but the sheet that came with the board said the hex address was 0x62, yet this returned 63? 


  If anyone has any suggestions I would appreciate any help. 

  Thank you, 
  

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Don't mind the errors prior to the last. I was messing with different i2c addresses in reef-pi. The last one is with everything entered as it should be.

[Rob F]

Hi sorry for the confusion, looks like I somehow missed changing the I2C address before I programmed it. If you change reef-pi driver to address 99 it should work ok. After you change the address you have to go to the configuration tab then admin tab and press the reload button.

[im_jeremy5]

That did not seem to work. After reloading I went to the connectors tab deleted, reloaded, and added new connector, reloaded again, then added the ph probe and I am getting the same error in reef-pi. Thank you for your quick response.

[Rob F]

That error should mean it can't communicate with the device so something maybe didn't get set correctly. Try deleting the pH from pH tab, then delete the connector, then the driver. Hit the reload button and add driver and connector, then reload button and add pH back. If you have any charts on home page delete those as well before adding back.

Another thing I should have mentioned is you need to slow down the I2C bus on the Pi however this isn't related to the error you have, without this you would get a parsing error.

• Open the Pi SSH terminal window
  
• run the command sudo nano /boot/config.txt
  
• When the file opens scroll down to this line dtparam=i2c_arm=on
  
• Add this line dtparam=i2c_arm_baudrate=10000 after the above
  
• Press CTRL + S on keyboard to save
  
• Press CTRL + Z to exit
  
• run the command sudo reboot
  

[im_jeremy5]

No dice. For good measure  I added screenshots of each step in case I am making a dumb mistake somewhere. I reloaded between each step and their are no pH charts on the dashboard. I also edited the boot/config.txt file as indicated above and rebooted

  Same error. 

  Thank you for your time.

               

[Rob F]

Thanks for the pictures, it all looks good but strange you see it with i2cdetect. Can you try the following. This will download a script to just read the pH circuit.

• Disable the pH in reef-pi
  
• Open SSH Pi terminal and run the following 3 commands.
  
• sudo wget -c https://www.robo-tank.ca/Robo-Tank_pH_Script.zip
  
• sudo unzip Robo-Tank_pH_Script.zip
  
• python Robo-Tank_pH_Script.py
  

After the 3rd command it will say Enter command:

Type in a capital R and press enter, it should return a pH value.

[im_jeremy5]

I might also add how it is hooke up.
My reef pi is built on a prototyping hat, similar to what is shown in the adafruit build guides by ranjib. On my hat I made a row of 5v i2c connectors for this and possibly future lighting control. I tested all of it specifically after I couldn't get this to connect and I have continuity to all connections where they are supposed to be. I soldered a header to the ribbon that was provided with the pH board to connect it to the hat.

My only concern is the ribbon runs in the general area of my buck converter. I was worried this might cause interference. But I thought that would result in bogus readings, not a total lack of connection.

[Rob F]

The connections are ok as the Pi I2C bus is seeing the ph circuit, that means it's definitely connected correctly. Were you able to try that standalone script, that should give an answer.

[im_jeremy5]

    Deleted all drivers and connectors in reef-pi, reloaded, then ran those commands in SSH

and it returned "Query Failed"

[Rob F]

Hmm, that's not good, typically that error represents the same error from reef-pi. How long is the total cable to connect the circuit? When you power up the pH circuit does the LED on it flash 3 times? Is it possible to post a picture of the connection to ribbon cable? Did you try the R command several times?

[im_jeremy5]

I am very thankful for your timely response, I wasn't expecting such a quick response when I made the post. ;) . I'm not going to be able to open up my reef pi until the morning.

  I did try that R command multiple times and same results every time. I'm not sure how many times it blinks, I will check in the morning and post a picture. The cable is the one sent with the pH board. Maybe 4 or 5 inches long.

[Rob F]

No problem, the cable does sound ok, certainly short enough but the fact the Pi detects it makes this all very strange also if it blinks during startup it is doing what it should. Another thing that might be worth trying, if you look on the pH circuit you'll see a pad marked "reset" if you have some tweezers or something short those 2 pads out for a few seconds until the LED on the circuit flashes 3 times. Once that happens it reset, then unplug the power to the circuit and power back up. At this point it seems something odd is happening in the processor, making no sense. If this doesn't work I'll have to send you another circuit.

[im_jeremy5]

I couldn't get a large enough photo to upload here, so here's an imgur link to the picture. https://imgur.com/gallery/okyaEtJ

  The green light flashes 3 times when power cycled. 

  I hit the reset jumpers until the light flashed on board.

  Unfortunately I still have the same error in reef-pi and "Query failed" using the above script.

[Rob F]

Thanks for trying, unfortunately I don't know what could be wrong, maybe I put too much heat on the processor when I mounted it and it's acting up. I'll have to send you another circuit, I'll send you a tracking number when I have it, sorry for the troubles.