Hi Bryan Here are the results: [quote userid="204916" url="~/support/data-converters-group/data-converters/f/data-converters-forum/1492482/ads1235-inconsistent-measurement-drift-and-step-changes-in-strain-gauge-system/5732800#5732800"]Does the performance change / improve if you change the programmable delay to something >0us?[/quote] I conducted another 4-hour test in the lab to observe how our device behaves in a controlled environment (no mechanical strains, temperature controlled with air conditioning, and a stable laboratory power supply). This time, I set the conversion start delay to 67 µs instead of 0 µs, as you suggested. Both ADCs still exhibit drift—one around 5,000 ADC levels and the other around 1,000 ADC levels. I’m starting to suspect that this is due to our sensor’s high sensitivity to temperature drift, as the strain gauges are referenced against a PCB-mounted voltage divider (consisting of two 1 kΩ resistors). [quote userid="204916" url="~/support/data-converters-group/data-converters/f/data-converters-forum/1492482/ads1235-inconsistent-measurement-drift-and-step-changes-in-strain-gauge-system/5732800#5732800"]Have you tried similar measurements with a known good source? For example, a AA battery (you would have to change the gain), or using a fixed resistor divider (3 resistors) that generates a low level voltage across the middle resistor that is within the PGA common-mode range?[/quote] I performed another 4-hour test using a fixed resistor divider (see block diagram) and set the conversion start delay to 67 µs. One of the ADCs showed a slight positive drift, while the other exhibited the step change in measurements that occasionally appears at random. I still haven’t been able to determine the cause of this behavior. Thanks for the support! Best regards, Edgar
↧