The wiring diagramms say:
"NTC Thermistor is used by default, PT100/Thermocouple (need AD597 add on) are also supported. 3.3V 4.7k pull-up"
in the Pinout it says then
So there is a 4.7k pullup on the Thermoinputs, what makes sense, as to read the thermistors u have a voltagem divider between the 4.7k and the thermistor, which then makes the input read a voltage.. Obvious.
In the features section it says:
"A 4.7kOhm 0.1% temperature sensor pull up resistor is used, PT1000 can be connected directly. For PT100, an amplifier board must be used."
the PT1000 with the 4.7k resistor also builds a votage divider where u could read the remaining voltage over it pretty precis.. At ambient the reading should be something like 18% 0.57V rising with rising temperature,
And with PT100 this should not work that proper and stable, as 4k7 vs 100 Ohm does not give a big reading and steps will be pretty little..
also Obvious.
So for thermocouples and also the PT100 one should use a amplifyer.. like AD597 or I'd even prefer AD8495 (advantage already running at 2.7V and with 5mV/K instead of 10mV/K it is hard to overvoltage the AIn of a STM... It's 330°C to 3.3V for the 597 and 660°C to 3.3V for the 8495)
But where to connect it? Just to the AIs with the pullup? Am not sure if this is right?
I'd like to ask for a little help.
The wiring diagramms say: "NTC Thermistor is used by default, PT100/Thermocouple (need AD597 add on) are also supported. 3.3V 4.7k pull-up" in the Pinout it says then
So there is a 4.7k pullup on the Thermoinputs, what makes sense, as to read the thermistors u have a voltagem divider between the 4.7k and the thermistor, which then makes the input read a voltage.. Obvious.
In the features section it says: "A 4.7kOhm 0.1% temperature sensor pull up resistor is used, PT1000 can be connected directly. For PT100, an amplifier board must be used." the PT1000 with the 4.7k resistor also builds a votage divider where u could read the remaining voltage over it pretty precis.. At ambient the reading should be something like 18% 0.57V rising with rising temperature, And with PT100 this should not work that proper and stable, as 4k7 vs 100 Ohm does not give a big reading and steps will be pretty little.. also Obvious.
So for thermocouples and also the PT100 one should use a amplifyer.. like AD597 or I'd even prefer AD8495 (advantage already running at 2.7V and with 5mV/K instead of 10mV/K it is hard to overvoltage the AIn of a STM... It's 330°C to 3.3V for the 597 and 660°C to 3.3V for the 8495) But where to connect it? Just to the AIs with the pullup? Am not sure if this is right?
Thank you for your help