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Topic: How to handle DallasTemperature 85 °C (Read 345 times) previous topic - next topic

MarkT

85 °C is in my expected operating range, and if TI has decided to signal an error or whatever state by sending a default temperature of 85 °C
Its just that the value of the temperature register is set to 85C at power up, and will read that until the
first conversion is complete.

Just arrange to wait for the first conversion to complete before reading the register and all will be well.
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

corcovado

Ooops!

I tried, then found out from datasheet it's not possible. Only three bytes are written to EEPROM.. :-(

photoncatcher

When I don't trust a readout of a DS18B20 (e.g in the 85 C range), I compare with a DHT11 or (better) with a BMP280. The BMP80 is a reliable I2C barometric pressure / air temperture sensor, and does not express '-127' and '85' errors.  

>>If one new or existing device does not work, compare with a known device <<
Succes !

corcovado

Photoncatcher,

Thanks, I try to live with Dallas now. Fortunately I have several sensors doubles, and I do the intelligent parts in web server, so my ESP8266 code remains clear.

I managed to get 85 degree values appearing by some connector cranking. While not really knowing what could have been the costs of having this configurable, I really see this something Maxim hopefully re-designs some day, or releases a new family.

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