Hi All,
I programmed a microcontroller to read NTC thermistor value, and send the temperature value to the PC with serial interface using USB cable.
I connected the NTC thermistor using voltage divider configuration as i found it very common online and its working OK.
(3.3V->Resistor->Thermistor->GND, while reading the voltage between the Thermistor leads)
In addition, I have another microcontroller that is completely separated from the first one, and it needs to send data through USB serial to the PC as-well.
Once I connect the second microcontroller, the temperature readings of the first microcontroller completely change to non reasonable values.
If I understand correctly, by connecting both USB cables to the PC, I'm actually connecting both microcontrollers GND's and it cause problem with the thermistor reading as the GND potential is not the same anymore.
Is there any way to isolate the thermistor's microcontroller GND, isolate the USB GND, or connect the thermistor differently to the microcontroller so it will not be affected by the second microcontroller?
Thanks in advance.
Nir.
I programmed a microcontroller to read NTC thermistor value, and send the temperature value to the PC with serial interface using USB cable.
I connected the NTC thermistor using voltage divider configuration as i found it very common online and its working OK.
(3.3V->Resistor->Thermistor->GND, while reading the voltage between the Thermistor leads)
In addition, I have another microcontroller that is completely separated from the first one, and it needs to send data through USB serial to the PC as-well.
Once I connect the second microcontroller, the temperature readings of the first microcontroller completely change to non reasonable values.
If I understand correctly, by connecting both USB cables to the PC, I'm actually connecting both microcontrollers GND's and it cause problem with the thermistor reading as the GND potential is not the same anymore.
Is there any way to isolate the thermistor's microcontroller GND, isolate the USB GND, or connect the thermistor differently to the microcontroller so it will not be affected by the second microcontroller?
Thanks in advance.
Nir.