Discussion in "Electronics" started by    esm    Feb 24, 2012.
Fri Feb 24 2012, 09:32 pm
#1
Hello.
I am using an external ADC (MCP3421), 16-bit resolution, with internal PGA (internal gain) of 8x to read signals from a thermocouple type T. Within my current ADC configuration, the differential input impedance is around 280K.
But when the inputs are floating, the result of ADC conversions behaves incorrectly (negative and positive aleatory values, sometimes with high values are read from ADC).

I want this ADC to output conversion values near to zero when the inputs are floating, to detect a sensor fault, or sensor disconnected, for example.

How could I do a "pull down" to it? because the Vin- input (reference) and Vin+ input (input signal) from the ADC and and the digital ground of the IC are not in the same voltage reference.

Get Social

Information

Powered by e107 Forum System

Downloads

Comments

BrettTibre
Fri May 17 2024, 06:14 pm
Gordonfax
Fri May 17 2024, 10:28 am
Davidspils
Fri May 17 2024, 10:19 am
Patricknoind
Fri May 17 2024, 09:53 am
JeremyCycle
Fri May 17 2024, 09:46 am
FrabSeby
Thu May 16 2024, 07:31 pm
PeterGem
Thu May 16 2024, 06:27 am
Timothywalay
Thu May 16 2024, 04:40 am