Thermistor Ring Protocols

Thermistor Ring Calibration

  • Thermistor ring outputs two sets of values: the raw °C values from the digital thermistors using the factory calibration and the calibrated values using the offset produced by calibration.

  • This calibration requires two points to be configured so that a linear calibration can be fit to the raw readings.

Thermistor Ring Calibration Commands

Note: These commands use RING01 as the id for the configured sensor. Use the correct id you have configured on your board for the thermistor ring sensor. Note: Calibration requires two known, stable temperature environments that the sensor can be exposed to.

  1. Configure the thermistor ring sensor (skip if already configured) rrivctl sensor set RING01 -f configuration/ring_temprature.json

  2. Clear existing calibration rivctl calibrate sensor RING01 clear

  3. Place the sensor in a known temperature environment, let it equilibrate, and set the first calibration point (here we are calibrating when the known temperature is 22.3°C, you must enter the correct temperater for your known temperature environment) rrivctl calibrate sensor RING01 point 22.3

  4. Place the sensor in a second, different known temperature environment, let it equilibrate, and set the first calibration point (here we are calibrating when the known temperature is 19.4°C, you must enter the correct temperater for your second temperature environment) rrivctl calibrate sensor RING01 point 19.4

  5. This command will list the current calibration values, which can be used to check your calibration points rrivctl calibrate sensor RING01 list

  6. Apply the calibration points to the raw data. A linear model is fit to the raw data. rrivctl calibrate sensor RING01 fit

  7. Now we can run the command below and we will see all the configs including the calibration. rrivctl sensor get RING01

Thermistor Ring Heater Control

Thermistor ring has a heater that turns on and off at regular intervals. This is variable depending on flow conditions. The heater is controlled by a relay that is controlled by GPIO Pin 8. Examples of configuration json files that can be used or edited for configuration are located in rriv-ctl/configurations. There is an example file called heater.json that has the correct format for configuring heater timing.

Thermistor Ring Heater Control Commands

  1. View the list of sensors. rrivctl list sensor

  2. Apply heater.json file as the heater configuration rrivctl set sensor HEATER -f configurations/heater.json

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