I need to monitor 12 nos of LM35 outputs in sequence. So I am trying to read the ADC in a round Robbin fashion.
I have LM35 outputs directly ( a RC LPF is there anyway!) goes to multiplexer, CD4065. then it goes to A Opamp based sallen key butterworth 2 pole filer and to PIC ADC. I plan to use this Opamp LPF because LM35 is mounted using 1.5 meters length shileded cable..
But the settling time of the filter will cause my sampling to be done at slower rate. High speed is not required anyway. How to calculate the settling time of a LPF filter to reach a optimum time?
thanks
I have LM35 outputs directly ( a RC LPF is there anyway!) goes to multiplexer, CD4065. then it goes to A Opamp based sallen key butterworth 2 pole filer and to PIC ADC. I plan to use this Opamp LPF because LM35 is mounted using 1.5 meters length shileded cable..
But the settling time of the filter will cause my sampling to be done at slower rate. High speed is not required anyway. How to calculate the settling time of a LPF filter to reach a optimum time?
thanks