Issue with O2 sensor

[jmFschneider]

Hello,

I add an application with two captors of oxigen and try you sample code.
First with one captor, and every think are going well.

Then I add the secon captor and I introduce modification of oxygen content in air (with CO2 formation).
One captor is in the flux of carbone dioxide, the second is in atmospgenric air. But I was supprise by the fact that the two oxigen values are till the same ! (ie the two value are going from 21.0% to 16.1%, Then when I remove the captor from this low oxigen content, the two values are going back to 21%.
If I reverse the captors, I observe the same behavior.

I follow what is appening on the I2C bus (with a logic analyser), and I see that the two captors are sending differents values when in low oxigen content.

But till now, not able to solve my problem.
Thanks you for your help !

Jean-Marie

The code I am using :

`# -- coding:utf-8 --
'''
  @file get_ozone_data.py
  @brief get ozone concentration, A concentration of one part per billion (PPB).
  @n step: we must first determine the iic device address, will dial the code switch A0, A1 (ADDRESS_0 for [0 0]), (ADDRESS_1 for [1 0]), (ADDRESS_2 for [0 1]), (ADDRESS_3 for [1 1]).
  @n Then configure the mode of active and passive acquisition, Finally, ozone data can be read.
  @n note: it takes time to stable oxygen concentration, about 3 minutes.
  @copyright Copyright (c) 2010 DFRobot Co.Ltd (http://www.dfrobot.com)
  @license The MIT License (MIT)
  @author ZhixinLiu
  version  V1.0
  date  2021-10-22
  @url https://github.com/DFRobot/DFRobot_Oxygen
'''
import sys
import time
import math
sys.path.append("../..")
from DFRobot_Oxygen import *

COLLECT_NUMBER   = 10              # collect number, the collection range is 1-100
IIC_MODE         = 0x01            # default use IIC1

'''
  The first  parameter is to select iic0 or iic1
  The second parameter is the iic device address
  The default address for iic is ADDRESS_3
  ADDRESS_0                 = 0x70
  ADDRESS_1                 = 0x71
  ADDRESS_2                 = 0x72
  ADDRESS_3                 = 0x73
'''
oxygen_1 = DFRobot_Oxygen_IIC(IIC_MODE ,ADDRESS_3)
oxygen_2 = DFRobot_Oxygen_IIC(IIC_MODE ,ADDRESS_0)

def oxy1():
  oxygen_data = oxygen_1.get_oxygen_data(COLLECT_NUMBER)
  return oxygen_data
 
 
def oxy2():
  oxygen_data = oxygen_2.get_oxygen_data(COLLECT_NUMBER)
  return oxygen_data

if name == "main":
  while True:
  oxygen = oxy1()
  print("oxygen Amont : %4.2f %%vol"%oxygen)
  time.sleep(1)
 
  oxygen = oxy2()
  print("oxygen Aval : %4.2f %%vol"%oxygen)
  time.sleep(1)`

[SergeyZh]

I'm not the author, but as far as I can tell from the library code, it doesn't support more than one sensor. It uses a single shared buffer, so in your case, it mixes data from both sensors.