User manual

1-Wire Application Guide v1.04 Page 16 of 41
The DS18B20 offers 9, 10, 11 or 12 bit resolution, or ± 0.5°C, ± 0.25°C, ±
0.125°C or ± 0.0625°C precision respectively. Temperatures can be measured
from –55°C to +125°C (-67°F to +257°F). Accuracy is ± 0.5°C (± 0.9°F) from –
10°C to +85°C. TEMP08 uses this device in 12-bit resolution mode.
Note: Waterproof DS18B20 sensors are available from RFXCOM Products at
http://www.rfxcom.com/sensors.htm#Additional or from other vendors on eBay.
These sensors can be used for pool, hot tub, or aquarium temperature
monitoring.
3.2.4 DS1822
The DS1822 offers 9, 10, 11 or 12 bit resolution, or ± 0.5°C, ± 0.25°C, ± 0.125°C
or ± 0.0625°C precision respectively. Temperatures can be measured from –
55°C to +125°C (-67°F to +257°F). Accuracy is ± 2.0°C (± 3.6°F) from –10°C to
+85°C. TEMP08 uses this device in 12-bit resolution mode.
3.2.5 DS2438
Even the DS2438 has temperature-sensing capability. It offers 13-bit resolution,
or a ± 0.03125°C precision. Temperatures can be measured from –55°C to
+125°C (-67°F to +257°F). Accuracy is ± 2.0°C (± 3.6°F) from –40°C to +85°C.
To use the DS2438 for temperature only, set the DS2438 type to “T”
(temperature).
3.2.6 Summary
0
0.1
0.2
0.3
0.4
0.5
0.6
DS18S20 DS18B20
DS1822 DS2438
0
0.5
1
1.5
2
2.5
Precision
Accurary
Figure 9 Sensor Comparisons