XY-MD02 Modbus temperature and humidity sensor: specs
A temperature and humidity module that carries a Sensirion SHT20 sensor and talks Modbus RTU over RS-485. Only the SHT20 sensor is documented here.
Specs
| Spec | Value | Source |
|---|---|---|
| Sensor supply voltage (SHT20 chip) | 2.1 V to 3.6 V, 3.0 V typ | source Electrical specification (p.2) |
| Humidity accuracy (SHT20, 25 C) | +/-3.0 %RH typ (maximum: Figure 2) | source Table 1 Relative Humidity (p.2) |
| Humidity normal operating range | 0 to 80 %RH (extended 0 to 100 %RH) | source Table 1 and footnote 4 (p.2) |
| Humidity resolution (SHT20) | 0.04 %RH at 12 bit; 0.7 %RH at 8 bit | source Table 1 (p.2) |
| Temperature accuracy (SHT20) | +/-0.3 C typ (maximum: Figure 3) | source Table 1 Temperature (p.2) |
| Temperature range (SHT20, extended) | -40 C to 125 C | source Table 1 (p.2) |
| Temperature resolution (SHT20) | 0.01 C at 14 bit; 0.04 C at 12 bit | source Table 1 (p.2) |
| Response time (63 percent) | Humidity 8 s; temperature 5 to 30 s | source Table 1 (p.2) |
Pinout
We don't publish a pin table for this part: no official source we could verify gives one. Check the labels printed on your module, and see the notes below.
The Sensirion sheet covers only the SHT20 sensor. The module's RS-485 terminals, supply and Modbus settings are not covered by an official document.
Build with it
Project ideas for the XY-MD02 Modbus temperature and humidity sensor. Each link opens Soldr with the prompt filled in; Soldr assigns the pins, checks power and shows how to wire every part.
- Modbus temperature and humidity reader: The converter board takes 3.3 V or 5 V logic from the ESP32 and drives the RS-485 pair. Get the module's register map, baud rate and address from its own documentation first. The module's own supply is not documented here: check the module label for its supply voltage and RS-485 terminals before wiring, and power it accordingly.
- Uno RS-485 climate display: The Uno and the MAX485 module both work at 5 V logic. Check the module's own documentation for baud rate and address. The module's own supply is not documented here: check the module label for its supply voltage and RS-485 terminals before wiring, and power it accordingly.
- Pico Modbus climate display: The Pico's 3.3 V UART fits the converter's 3.3 V logic option. Learning project; confirm the module's register map before reading values. The module's own supply is not documented here: check the module label for its supply voltage and RS-485 terminals before wiring, and power it accordingly.
Common mistakes
- Quoting the SHT20 chip supply (2.1-3.6 V) as the module's supply: the module board's supply range is not documented here (source: link, p.2)
- Expecting stable readings above 80 %RH for long periods: the sheet says long exposure outside the normal 0-80 %RH range can shift readings (source: link, Section 1.1 Operating range and footnote 4)
Not covered by the official source
- No maker document for the XY-MD02 module; Modbus registers, baud rate, default address and supply are not stated.
- SHT20 values describe the sensor only.
- The module's supply voltage and RS-485 terminal labels are not in any maker document found; the ideas tell the builder to check the module label.
Sources
- link (Sensirion SHT20 datasheet, Version 5, October 2022)