ADS1230

This library allows a raspberry pi to communicate with an ADS 1230 20 bit ADC, which is usually used in load cells or pressure sensors. Supported features right now are

• trigger offset calibration
• pull measurements
• accidental standby protection
• direct conversion of measurements to units

For now the library expects the ADS1230 to be configured with the SPEED pin pulled to GND as the corresponsing timings are hardcoded into the source.

State of the project

At the moment the library does exactly what I need it to do. I've implemented the usecases I need while omitting several features of the chip that I do not need. If you require additional functionality feel free to open an issue and I might add it. Also feel free to fork, I'll happily accept pull requests.

Installing

I have not published this library to PyPi yet. For now you need to clone the repository and install it yourself.

This library depends on RPi.GPIO

Usage

In a loadcell/weight sensor

from ads1230 import Loadcell

sensor = Loadcell(5,6)  # PIN_SCKL, PIN_DOUT
sensor.calibrate_zero()
# now place a reference weight on your sensor
sensor.calibrate_unit(1.0)  # the fraction indicates the ratio of your reference weight to your reference unit
# eg if you want to measure kilogram and your reference is 500g you need to use a fraction of 0.5

result = sensor.measure()

You can save the calibration by storing sensor.unit_value and restoring it upon restart. This way you won't need to calibrate the reference unit on every restart. You should however sensor.calibrate_zero() on every restart.

Just the ADC

from ads1230 import ADS1230
import time

ads = ADS1230(5,6)  # PIN_SCKL, PIN_DOUT
ads.calibrate()  # puts the device into calibration mode.
while not ads.is_ready():  # Wait until data is available
    time.sleep(0.1)
raw = ads.measure()  # read one measurement

Notes on timing

The ADS1230 has some tight requirements on SCLK pulse timings. So far I've tested this only on a Raspberry PI 4 and I do not know if previous models are able to act fast enough to prevent the ADS1230 from going into sleep mode. The library automatically measures the timing of the SCLK pulses and aborts a measurement with an ADS1230TimingViolatedExcception when violated. Even on a Raspberry PI 4 occasional appearances of this exception are expected, for example when interrupted by a context switch.