What does "optimised for" in the temp sensor specs mean?

[ersin]

In the specs for the Duet 3 Mini 5+, it says that the temperature sensor inputs are "optimised for 100K thermistors and PT1000 sensors."

What does "optimised for" mean here? Aren't the settings for all temp sensors configured via firmware? Is there some kind of hardwired bias in favor of these particular sensors?

[dc42]

@ersin the series resistors used to read thermistors are typically 4.7K to give good resolution over a wide range of temperatures when using 100K thermistors. However, 4.7K isn't ideal for reading PT1000 sensors. So we use 2.2K on more recent Duets to give better resolution when using PT1000 sensors, while still providing excellent resolution when using 100K thermistors.

[ersin]

@dc42 understood, thank you for clarifying.

Can you shed a little more light onto why 4.7K resistors aren't ideal for reading PT1000 sensors? Or point me in the right direction toward a good resource that might explain it in more depth?