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Usage

Once the device is assembled, flashed, and wired, it is ready to communicate over a serial port. It is designed to integrate with automation systems like laser_setup that use the PT100SerialSensor interface.

Basic usage:

Connect the device to a computer or lab system via USB-to-Serial converter. Open a serial terminal (e.g., minicom, screen, Arduino IDE Serial Monitor) at 115200 baud, 8 data bits, no parity, 1 stop bit.

Send the command R (followed by a newline, though the firmware will process it immediately): 

R

The device will respond with a single line of CSV data: 

<milliseconds_since_boot>,<PT100_temperature>,<DS18B20_temperature>

Example output: 

R
45023,24.32,23.8

This means 45023 ms have elapsed since boot, the PT100 sensor reads 24.32°C, and the DS18B20 reads 23.8°C.

To query the device identity, send *IDN?: 

*IDN?
ROSATECH,TSN100,P0000002,1.0.1

Integration with laser_setup:

The PT100SerialSensor class in laser_setup expects to: 1. Open a serial port at 115200 baud 2. Send the command R followed by a newline 3. Receive a response line matching the pattern <clock>,<plate>,<ambient> 4. Parse the three comma-separated values as floats

The firmware output exactly matches this protocol. Ensure the serial port device path is correctly specified in laser_setup configuration (typically /dev/ttyUSB0 on Linux or a COM port on Windows).

Sensor characteristics:

  • PT100 (MAX31865): Industry-standard platinum RTD. Provides precise, stable temperature readings over a wide range. Typical accuracy ±0.5°C after calibration. Used for "plate" temperature (main measurement).
  • DS18B20 (OneWire): Dallas digital temperature sensor. Fast response, good for ambient monitoring. Typical accuracy ±0.5°C. Used for "ambient" temperature (secondary channel).

Both sensors are read on each R command. If either sensor is disconnected or fails, the output may contain NaN or invalid values; implement error handling in the consuming application as needed.

Troubleshooting:

  • Device not responding: Verify the serial port is connected at 115200 baud. Check that the ESP8266 is powered (LED should be lit). Confirm that the MAX31865 and DS18B20 are correctly wired.
  • MAX31865 returns 0 or invalid readings: Check SPI wiring (MOSI, MISO, SCK, CS). Verify the CS pin is GPIO15 (D2) and properly pulled. Confirm the PT100 sensor is connected to the MAX31865 module.
  • DS18B20 missing or stuck at high temperature: Check OneWire wiring to GPIO2 (D4). Verify the 4.7 kΩ pull-up resistor is present between VCC and the data line. Confirm the sensor is properly seated.
  • Garbage output on serial: Verify baud rate is exactly 115200. Check USB-to-Serial converter drivers are installed. Try a different USB port or converter if issues persist.