ADC Differential Pi Python Library

Python Library to use with ADC Differential Pi Raspberry Pi development board

The example python files can be found in /ABElectronics_Python_Libraries/ADCDifferentialPi/demos

Downloading and Installing the library

To download to your Raspberry Pi type in the terminal:

git clone https://github.com/abelectronicsuk/ABElectronics_Python_Libraries.git

To install the python library navigate into the ABElectronics_Python_Libraries folder and run:

For Python 2.7:

sudo python setup.py install

For Python 3:

sudo python3 setup.py install

If you have PIP installed you can install the library directly from GitHub with the following command:

For Python 2.7:

sudo python2.7 -m pip install git+https://github.com/abelectronicsuk/ABElectronics_Python_Libraries.git

For Python 3:

sudo python3 -m pip install git+https://github.com/abelectronicsuk/ABElectronics_Python_Libraries.git

The ADC Differential Pi library is located in the ADCDifferentialPi directory

The library requires smbus2 or python-smbus to be installed.
For Python 2.7:

sudo pip install smbus2

For Python 3:

sudo pip3 install smbus2

Classes:

ADCDifferentialPi(address, address2, rate, bus)

Parameters:
address: I2C address for channels 1 to 4, defaults to 0x68
address2: I2C address for channels 5 to 8, defaults to 0x69
rate: bit rate, values can be 12, 14, 16 or 18. Defaults to 18
bus (optional): I2C bus number (integer). If no value is set the class will try to find the i2c bus automatically using the device name.

Functions:

read_voltage(channel) 

Read the voltage from the selected channel
Parameters: channel - 1 to 8 Returns: number as a float between -2.048 and +2.048

read_raw(channel) 

Read the raw int value from the selected channel
Parameters: channel - 1 to 8 Returns: number as an int

set_pga(gain)

Set the gain of the PGA on the chip
Parameters: gain - 1, 2, 4, 8
Returns: null

set_bit_rate(rate)

Set the sample bit rate of the ADC
Parameters: rate - 12, 14, 16, 18
Returns: null
12 = 12 bit (240SPS max)
14 = 14 bit (60SPS max)
16 = 16 bit (15SPS max)
18 = 18 bit (3.75SPS max)

set_conversion_mode(mode)

Set the conversion mode for the ADC
Parameters: mode - 0 = One-shot conversion, 1 = Continuous conversion
Returns: null

Usage

To use the ADC Differential Pi library in your code you must first import the library:

from ADCDifferentialPi import ADCDifferentialPi

Next, you must initialise the ADCDifferentialPi object:

adc = ADCDifferentialPi(0x68, 0x69, 18)

The first two arguments are the I2C addresses of the ADC chips. The values shown are the default addresses of the ADC board.

The third argument is the sample bit rate you want to use on the ADC chips. The sample rate can be 12, 14, 16 or 18

You can now read the voltage from channel 1 with:

adc.read_voltage(1)