Try to use ph sensor this raspberry pi.

Hi. I want start use PH sensor on rasberry PI.
Found on git https://github.com/DFRobot/DFRobot_PH/t ... stallation.
Try to start:
/home/pi/DFRobot_PH/RaspberryPi/Python/example# python DFRobot_PH_Read.py
And see this:
Traceback (most recent call last):
File "DFRobot_PH_Read.py", line 26, in <module>
adc0 = ads1115.readVoltage(0)
File "../DFRobot_ADS1115.py", line 142, in readVoltage
self.setSingle()
File "../DFRobot_ADS1115.py", line 110, in setSingle
bus.write_i2c_block_data(addr_G, ADS1115_REG_POINTER_CONFIG, CONFIG_REG)
IOError: [Errno 121] Remote I/O error

PS:
Rasberry pi b+ ver 1.2
pin 4,6(5V) and 3(I2C)
diagramm from hear https://pi4j.com/1.2/pins/model-b-plus.html