i use an ad7709 to measure thermocouple signal, and there is a problem:
1. input channel:AIN1 and AIN2.
2. use pseudo-bipolar mode.
1. when i operated as follow process:
hardware reset (use reset pin ) --> read first data --> read second data --> end
then, both datas were wrong.
2. when i only read one data,
hardware reset --> read first data --> end
then, the data was right.
and i also have some questions:
1. do i need to calibrate the product after manufacture?
i read datasheet that, the device is factory-calibrated at final test. however, we will use different voltage reference, is that still ok?
2. do i need to care about zero shift?,
in most ad converters, this is a serious problem, so is it same with this device?