CALCE - ePrognostic Systems PHM Sensor Tag
In partnership with ePrognostic Systems, the CALCE PHM team is developing low-cost, programmable, active RFID sensor tags for autonomous environmental monitoring. The tag has embedded sensors to monitor temperature, humidity, acoustic and vibration (3-D accelerometer) as well as external sensors. It has an integrated chip include memory, processor and wireless communications to store data, process and transfer data. The tag is powered by thin battery technology. The tag is sealed in laminated layers and self adhesive. It can be used in a harsh environment. The CALCE-ePrognostic software is used activate and configure the tag wirelessly. The software can show the data, plot the figure, andsave the data into text files. The system is open-architected.
The operating frequency of the sensor tag's RFIDis 13.56 MHz. The range of the transmission depends on the radio frequency used. This tag can be beprogrammed to set the sample rate and mode, configured to enable variable reading distances, turn on the wireless capability on as is needed basis which is indicated by LED to save battery power. It transmits data to the reader on request.
The sensor tag allows a user to specify upper and/or lower thresholds, thereby increasing the utility of the data storage memory. This eliminates unnecessary recordings and memory consumption. In applications where the equipment sits idle much of the time, idle readings need not consume valuable memory space.
Another useful programming feature is “delayed start”. If a user knows there will be some delay time between installation and operation, the user can opt to save memory space wasted by samples taken during that delay by specifying a “delayed start”time in units of minutes, hours or days.
After the tag has been programmed, it can monitor and record autonomously. The onboard battery allows the tag to operate for up to approximately 20,000logging cycles (the equivalent of 1 year). Each data point includes time stamps. Each tag has a unique identification number which enables the reader to distinguish each tag when multiple tags are being used.
