I was recently asked if the T400 battery is rechargeable and how the USB data connection works.
The BL-5C battery in the T400 is rechargeable. It will charge while the T400 is connected via MicroUSB cable. The battery status indicator icon () will show the battery charge state. While charging the icon will be animated. When the battery is full the icon will be full and solid. You can expect a battery life of approximately 60 hours.
The T400 acts as a serial port when connected via USB. Ascii data will stream from the T400 in the same format as the CSV file on the MicroSD card. The T400 does not react to any commands, so there's no need to send any control commands. It just always streams data.
You can capture the serial stream using serial logging software like Serial Data Logger on Windows. For Linux I recently discovered SerialPlot, which will graph data as it comes in. This can then be exported to CSV.
Here is a screenshot of some data I exported using SerialPlot.
Here is a sample of the serial data output after pressing the start/stop logging button. The first line is the firmware version. The second line is the file name. The third line is the column heading with the time in seconds followed by the temperature channels. The measurement units are indicated in parentheses. The remaining lines are the data points. In this case, temp_3 has no thermocouple connected.
time (s), temp_0 (C), temp_1 (C), temp_2 (C), temp_3 (C)
0, 24.96, 25.14, 25.53, -
1, 24.96, 25.14, 25.53, -
2, 24.96, 25.14, 25.53, -
3, 24.96, 25.14, 25.53, -
4, 24.91, 25.09, 25.48, -
5, 24.96, 25.14, 25.53, -
If there is enough interested I can make a serial logging program. Can you describe your vision of a basic logging program?