Hi,
It may be that I'm worrying about nothing here, but just in case .
I have a load of NTC like this https://www.circuitlab.com/circuit/btt9cg/100k-ntc-circuit/ connected to ADC channels 19-27. There are a load of digital inputs and outputs on the other pins.
Thinking I have set up the ADC ok, there is always a 10mV or more drop across the 22k to the PICaxe pin with my Fluke 1587 DMM.
Surely the input impedence of the ADCs in the 100s of Megs or even a gig?
ADCset up is this:
Am I missing something obvious? (no one is infallible after all ).
Regards
Eclectica
It may be that I'm worrying about nothing here, but just in case .
I have a load of NTC like this https://www.circuitlab.com/circuit/btt9cg/100k-ntc-circuit/ connected to ADC channels 19-27. There are a load of digital inputs and outputs on the other pins.
Thinking I have set up the ADC ok, there is always a 10mV or more drop across the 22k to the PICaxe pin with my Fluke 1587 DMM.
Surely the input impedence of the ADCs in the 100s of Megs or even a gig?
ADCset up is this:
Code:
adcsetup2 = %0000111111111000 ;boiler header, outlet, topstat, midpocket, botstat, bflow, bretn, tint, tout (ADC19-ADC27)
Regards
Eclectica