Part Number: ADS124S08 I have a PCB using ADS124S08 for ratiometric measurement of two 4-wire RTD's. These use the pins AIN0-AIN05, REFP0, REFN0, REFP1/AIN6, REFN1/AIN7 and it works great (thanks to help I got in this forum). Connected to AIN8, I have a standard 100k NTC Thermistor (MPN: NB12SC0104JBB) that is connected as in the schematic below. When measuring with a multimeter on the test point W9, I get 1.67V. When I increase the temperature of the NTC, it rises and falls very precisely, so electronically all is good. My problem is measuring this with the ADC. According to the datasheet, I've found that to do single-ended measurements, I have to set the PGA in BYPASS mode. I've also found that single-ended measurements should use AINCOM as a reference. AINCOM is connected to GND. I'm unable to find anything else that I have to do to make this work, but the readings are very low and do not reflect the temp in any way. I've also tried replacing AINCOM with AIN9 connected to GND, with no sensible results. I suspect that there's just a single, tiny bit of info that I've missed in the datasheet that prevents the ADC from measuring AIN8, but I'm unable to find it. Can someone please help me set the registers right for single ended measurements on this ADC?
↧