ZHCSKD9 October 2019 ADS1235-Q1
PRODUCTION DATA.
To user calibrate, apply the calibration voltage, acquire conversion data, and compute the calibration value. The computed value is written to the corresponding calibration registers. Before starting calibration, preset the offset and full-scale registers to 000000h and 400000h, respectively.
To offset calibrate, short the ADC inputs (or inputs to the system) and average n number of the conversion results. Averaging conversion data reduces noise to improve calibration accuracy. Write the averaged value of the conversion data to the offset registers.
To gain calibrate using a full scale calibration voltage, temporarily reduce the full scale register 95% to avoid output clipped codes (set FSCAL[2:0] to 3CCCCCh). Acquire n number of conversions and average the conversions to reduce noise to improve calibration accuracy. Compute the full-scale calibration value as shown in Equation 5:
where