Environmental
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LI-7000: Digital CPU Board
The LI-7000 features a digital CPU board for faster data output rates and real time graphing on the front panel, and USB connectivity. A digital board upgrade is also available for LI-7000s currently in the field. (For more info, download the LI-7000 Digital Board Data Sheet.) A Summary of the features is listed below:
| Feature | New Board | Previous Board | Benefit |
| Microprocessor | 400 MHz | 40 MHz | The new microprocessor (10x faster) provides interfacing flexibility when integrating the LI-7000 into other systems (i.e. carbon cycle measurement system). |
| USB Interface | Yes | No | Now you can use a super fast USB port (2.0 compliant) to collect, monitor and configure the LI-7000 in real-time. |
| RS-232 Baud Rates | 9600 to 115200 | Fixed @ 9600 | A choice of multiple baud rates (9600-115,200 bps) allows flexibility in custom data acquisition programs. Increased speed is important when collecting data from multiple serial devices on the host computer. |
| Data Checksum | Yes | No | The data checksum feature ensures the integrity of digital data (RS-232 & USB) transmitted between the LI-7000 and a computer. This is important in electrically noisy environments where high flow rate pumps could induce noise into data cables. |
| Auxiliary Input Bandwidth | 10 Hz | 0.45 Hz | Increased auxiliary input voltage bandwidth allows data from fast response sensors (such as from a sonic anemometer) to be input into the LI-7000. The auxiliary input results can be output along with the LI-7000 measurements as a single data string to the USB and RS-232 ports. |
| Data Transfer Rates | Up to 50 Hz | Up to 20 Hz | Significant when measuring small, fast moving eddies close to the ground or in aeronautical applications. |
| DAC Output Update Rate | 600 Hz | 300 Hz | Four 14-bit user-scalable Digital-to-Analog Converters (DAC) update rates are increased from 300 Hz to 600 Hz. Analog representation of LI-7000 measurements such as concentration, temperature and pressure data can be fed into high speed dataloggers or sonic anemometers supporting an analog to digital converter. |
| Real-Time Graphing on front panel | Yes | No | New software now includes real-time graphics on the LI-7000 display. |
| External Input Trigger Signal via RS-232 port | Yes | No | An external trigger signal input is now available via the RS-232 port. This is a tool that allows an external host computer or datalogger to poll the LI-7000 for the closest 1/600 s measurement (e.g. CO2, H2O, Temperature, Pressure, Diagnostics) in order to synchronize with data from another device such as a sonic anemometer. The serial data request is then transmitted to both the RS-232 and USB interfaces. |
