Features and Benefits
- Digital thermometer measures temperature 1/8°C increments with ±1°C accuracy
- Built-in real-time clock (RTC) and timer has accuracy of ±2 minutes per month from 0°C to 45°C
- Water resistant or waterproof if placed inside DS9107 iButton capsule (Exceeds Water Resistant 3 ATM requirements)
- Automatically wakes up and measures temperature at user-programmable intervals from 1 to 255 minutes
- Logs consecutive temperature measurements in 2KB of datalog memory
- Records a long-term temperature histogram with 1/2°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 battery-backed SRAM
- Communicates to host with a single digital signal at 15.4kbits or 125kbits per second using 1-Wire protocol
- Fixed range: H: +15°C to +46°C; Z: -5°C to +26°C
- Digital identification and information by momentary contact
- Unique, factory-lasered and tested 64-bit registration number (8-bit family code + 48-bit serial number + 8-bit CRC tester) assures absolute traceability because no two parts are alike
- Multidrop controller for 1-Wire net
- Chip-based data carrier compactly stores information
- Data can be accessed while affixed to object
- Button shape is self-aligning with cup-shaped probes
- Durable stainless steel case engraved with registration number withstands harsh environments
- Easily affixed with self-stick adhesive backing, latched by its flange, or locked with a ring pressed onto its rim
- Presence detector acknowledges when reader first applies voltage
The Thermochron® iButton® devices (DS1921H/Z) are rugged, self-sufficient systems that measure temperature and record 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 64 data bins with a resolution of 0.5°C. If the temperature leaves a user-programmable range, the DS1921H/Z 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. Additional 512 bytes of general-purpose battery-backed SRAM allow storing information pertaining to the object to which the DS1921H/Z is associated. Data is transferred serially via the 1-Wire® protocol, which requires only a single data lead and a ground return. Every DS1921H/Z 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 DS1921H/Z to be mounted on almost any object, including containers, pallets, and bags.
Product Lifecycle Production
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
Evaluation Kits (1)
The DS1921K Thermochron™ iButton® Starter Kit provides the basic hardware for a quick evaluation of Maxim’s Thermochron iButton family that communicates using the 1-Wire® protocol. The kit uses the USB port of a Microsoft Windows®-based Personal Computer running Vista®, XP SP2 (or higher), or Microsoft Server Operating Systems Windows 2003 or 2008. The kit includes a DS1921 Thermochron iButton device and all hardware required to communicate with it. The DS1921K is also capable of evaluating any other iButton devices, including the high-capacity Thermochron devices (DS1922L, DS1922T, and DS1923), the Hygrochron™ device (DS1923), and the temperature-only iButton device (DS1920). Please note that the DS1921 is the only iButton device included in the kit. All other iButton devices may be purchased separately. The easy setup process includes the free download of 1-Wire drivers and the OneWireViewer demonstration software to easily communicate with iButton devices through the PC's USB port. The download site for the free 1-Wire drivers and bundled OneWireViewer is found at:
For software developers who wish to create custom iButton applications, Maxim provides documentation and a free library of source code examples at www.maximintegrated.com/ibutton under the Software Development Kits link. Please check our website regularly for software updates.
To evaluate plastic-packaged 1-Wire devices instead of the iButton form factor, use the DS9090K instead of the DS1921K. To evaluate other iButton devices besides the Thermochron devices, see the DS9092K.
EV Kit Contents
|1||DS1921G-F5# Thermochron iButton|
|1||DS9093F Snap-in Fob, Black|
|1||DS1402D-DR8 dual Blue Dot™ Receptor|
|1||DS9490R USB to 1-Wire adapter|
Features & Benefits
- Starter Kit to evaluate the DS1921 Thermochron iButton temperature recording device with a Microsoft Windows-based PC
- Easy Setup with USB Adapter
- Free download of 1-Wire drivers and OneWireViewer Demonstration Software
- Compatible with other Thermochron iButton devices DS1922L, DS1922T, DS1922E, DS1923 (not included)
Documentation & Resources
DS1921H Reliability Data1/12/2023
Choosing the Logger iButton That's Right for You5/11/2012
1-Wire Software Resource Guide Device Description7/8/2008
Overview of iButton® Sensors and Temperature/Humidity Data Loggers8/21/2006
What Is an iButton Device?5/17/2006
White Paper 7: Thermochron® Mission Authentication and Security9/10/2002
ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal.
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