Part Number: ADS1247 Hi, We have a fully functional PLC design using the ADS1247 for configurable multi-mode analog input (U / I / RTD), and getting into mass production right now. We have just figured out, while working on an RTD calibration software utility, that the ADS1247 displays measurement offset errors of up to 0.5% when we unplug and re-plug live the I/O terminals for changing from a 100R to a 250R precision resistors set used for calibration. Further investigations have shown that when the ADS1247 is powered up without the RTD load being connected, then it will also display that offset error. When the offset error is present, it will stay for ever, as long as the ADS1247 configuration isn't changed. But when changing the configuration (changing the PGA gain isn't sufficient, we have to apply changes to the MUX: e.g. to switch back to voltage input mode, than return to RTD input mode) the offset error will disappear). Is there any explanation why the ADS1247 does display that offset error when losing the RTD load, or powering up without the RTD load ? Monitoring the RTD IDAC current didn't display any change in it when the issue arises. Changing the PGA setting alone doesn't make the offset error to disappear. Is it a MUX issue ? Or a REFP / REFN issue ? Many thanks for your help.
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