Analog AD7193 problem

Hello, i dont have much time to help you with your problem, but i can tell you what first comes on my mind when i read your text. Your wire, if other end is in the air, can collect some noise from everywhere when its floating like that. so, if you want 0 on your input, connect it to the ground and check your output. If output falls to zero when you connect input to GND, the problem is solved. If this help you, award me, if not, ignore. good luck with your project

A proposal has not yet been provided

Hi, Have you configured in proper way the CONFIGURATION REGISTER of the AD7193?It looks the inputs can be also configured in pseudo differential way. Cheers Ugo Fabrizi

Have you checked spectrum of the signal you are getting? In normal environment, 5-20mV can be explained by induced voltage from power grid, with your ADC speed it should be easy to check. Overall, proper cable shielding is really important, and if you need to make precise measurements, the best practice is to place amplifier or ADC as close to the sensor as possible, preferably on the same pcb. If you can explain what exactly you want to measure with this, I might be able to propose some ways to eliminate noise

What you are doing by adding an open ended cable is effectively placing an antenna in the circuit. To get an accurate measurement the differential input requires a minimum source current.