The DS1921G Thermochron® iButton® is a rugged, self-sufficient system that measures temperature and records the result in a protected memory section. The recording is done at a user-defined rate, both as a direct storage of temperature values as well as in the form of a histogram. Up to 2048 temperature values taken at equidistant intervals ranging from 1 to 255 minutes can be stored. The histogram provides 63 data bins with a resolution of 2.0°C. If the temperature leaves a user-programmable range, the DS1921G will also record when this happened, for how long the temperature stayed outside the permitted range,and if the temperature was too high or too low. An additional 512 bytes of read/write NV memory allow storing information pertaining to the object to which the DS1921G is associated. Data is transferred serially via the 1-Wire protocol, which requires only a single data lead and a ground return. Every DS1921G is factory-lasered with a guaranteed unique electrically readable 64-bit registration number that allows for absolute traceability. The durable stainless steel package is highly resistant to environmental hazards such as dirt, moisture, and shock. Accessories permit the DS1921G to be mounted on almost any object, including containers, pallets, and bags.
- Digital thermometer measures temperature 0.5°C increments
- Accuracy ±1°C from -40°C to +70°C. See EC table for accuracy specification
- Built-in real-time clock (RTC) and timer has accuracy of ±2 minutes per month per month from 0°C to 45°C
- Automatically wakes up and measures temperature at user-programmable intervals from 1 to 255 minutes
- Logs up to 2048 consecutive temperature measurements in protected nonvolatile (NV) random access memory
- Records a long-term temperature histogram with 2.0°C resolution
- Programmable temperature-high and temperature-low alarm trip points
- Records up to 24 time stamps and durations when temperature leaves the range specified by the trip points
- 512 bytes of general-purpose read/write NV random access memory
- Communicates to host with a single digital signal at 15.4kbits or 125kbits per second using 1-Wire® protocol
Datasheet available here.