DS1921G: Thermochron iButton Device Data Sheet (Rev. 9)4/1/2015444K
Features and Benefits
- High Accuracy, Full-Featured Digital Temperature Logger Simplifies Temperature Data Collection and Dissemination of Electronic Temperature Record
- Accuracy ±1°C from -30°C to +70°C (See the Electrical Characteristics for Accuracy Specification)
- Digital Thermometer Measures Temperature in 0.5°C Increments
- Built-In Real-Time Clock (RTC) and Timer Has Accuracy of ±2 Minutes per Month from 0°C to +45°C
- Automatically Wakes Up and Measures Temperature at User-Programmable Intervals from 1 Minute to 255 Minutes
- Logs Consecutive Temperature Measurements in 2kB of Datalog 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 Timestamps and Durations When Temperature Leaves the Range Specified by the Trip Points
- Individually Calibrated in a NIST-Traceable Chamber
- Complies to Standard EN12830
- 512 Bytes of General-Purpose Battery-Backed SRAM
- Rugged Construction Survives Harsh Environments
- Water Resistant Enclosure (IP56) or Waterproof if Placed Inside DS9107 iButton Capsule (Exceeds Water Resistant 3 ATM Requirements)
- CE, FCC, and UL913 Certifications
- Simple Serial Port Interfaces to Most Microcontrollers for Rapid Data Transfer
- Communicates to Host with a Single Digital Signal Up to 15.4kbps at Standard Speed or Up to 125kbps in Overdrive Mode Using 1-Wire Protocol
The Thermochron® iButton® device (DS1921G) 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 255min 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 also records 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 battery-backed SRAM allow storing information pertaining to the object to which the DS1921G is associated. Data is transferred serially through 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.
- Temperature Logging in Cold Chain, Food Safety, Pharmaceutical, and Medical Products
Product Lifecycle Recommended for New Designs
This product has been released to the market. The data sheet contains all final specifications and operating conditions. For new designs, ADI recommends utilization of these products.
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
DS1921G Reliability Data1/12/202312K
UG-5917: Instructions for Compiling the OneWireViewer for Linux6/15/2015780K
Thermochron Code Migration8/11/2022
Interface 1-Wire USB Adapter with Android3/12/2015
Determining the Mission Parameters for Temperature Logger iButton® Devices3/29/2012
OneWireViewer Tips and Tricks6/13/2011
1-Wire Search Algorithm3/28/2002
Reading and Writing 1-Wire® Devices Through Serial Interfaces3/29/2001
Advanced 1-Wire Network Driver2/14/2023
iButton Data Loggers5/17/2019
Choosing the Logger iButton That's Right for You5/11/2012
1-Wire Software Resource Guide Device Description7/8/2008
Overview of 1-Wire Technology and Its Use6/19/2008
Software Methods to Achieve Robust 1-Wire® Communication in iButton® Applications9/11/2007
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
Exporting Thermochron Data to Excel9/9/2002
White Paper 5: Using 1-Wire APIs for Data Sheet Commands6/7/2002
1-Wire Communication Through Software5/30/2002
Using the DS2480B Serial 1-Wire® Line Driver3/12/2002
Guidelines for Reliable Long Line 1-Wire Networks11/16/2001
1-Wire File Structure7/11/2001
Understanding and Using Cyclic Redundancy Checks with Maxim 1-Wire and iButton Products3/29/2001
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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