October 2017:
FireBoard is pleased to announce yet another powerful feature — support for multiple types of temperature probes. No other thermometer in this class (that we are aware of) can support this type of amazing flexibility. FireBoard can officially support RTD PT-100, 100K Thermistors and 10K Thermistors — all in one device.
There are advantages and disadvantages to both types of sensors. For general bbq / cooking use, most likely Thermistors offer a good balance between usability and accuracy. For extended temperature ranges (especially higher temperatures) RTDs are probably a good choice.
This information page shares our knowledge base of the characteristics between these probes, and for those that are interested, delves into the science of what makes these probes different from one another.
Which type of probe do I have?
Starting in October 2017, FireBoard started shipping all thermometers standard with 100K Thermistors. FireBoards sold prior to that date shipped with RTD probes. You can tell which type you have by the 2.5mm audio plug. Look closely, its a subtle yet noticeable difference so you can distinguish between the two types.
As we will outline below, its really up for debate which type is better, and each type has pros and cons.
How do I select a different probe type?
Probe type can be selected on a per channel basis
You can select which probe type you are using from the FireBoard app. Simply visit the Device page, then select Advanced Settings – from there you’ll see the Probe Configuration option that will allow you to change the probe type on a per channel basis.
The Science behind Temperature Probes
In short, a temperature probe is really a small sensor encased in a tube. The sensor is usually a type of metal or ceramic which varies its electrical resistance with temperature. For example, a typical RTD probe is platinum metal, and its resistance is exactly 100 ohms at 0°C.
We spent a lot of time in the calibration lab running temperatures!
It’s resistance is positively correlated to temperature and it exhibits a linear relationship. In contrast, the Thermistors we use have 100,000 ohms of resistance at 25°C and carry an inverse, non-linear relationship to temperature.
Because the Thermistor carries a much higher resistance, it is less sensitive to small changes in resistance (i.e., noise) which make it a good choice for cooking / bbq. The RTD however is more sensitive and accurate, yet more prone to noise outside of a controlled environment. Both types provide good temperature readings, and the case can be made why either type should be used.
For even more technical information, this article digs even deeper into the technical details of what a Thermistor and RTD really is. https://www.bapihvac.com/application-note/thermistor-vs-rtd-temperature-measurement-accuracy-application-note/
Thermistor
- Faster response time (~5 seconds)
- Excellent choice for BBQ and the Kitchen
RTD
- Can measure temperature across a wider range (-58 to 715F)
- Suitable for extreme temperature environments
| Thermistor Probes | RTD Probes | |
|---|---|---|
| Response Time | ||
| Temperature Range | ||
| Convenience | ||
| Probe Sizes | ||
| Calibration |