The TRANBALL QM7903V user manual provides technical specifications, wiring options, communication protocols, and operation instructions for the noise…
The QM7903V is an industrial noise monitoring device that supports multiple output interfaces such as RS485, TTL, DC0‑3V, and various wireless options. It features a high‑precision sensor core for reliable noise measurement across a wide range.
The manual covers technical parameters, product selection, wiring diagrams, Modbus‑RTU communication protocol, command frames for reading and configuring the device (address, baud rate, calibration), and calculation methods for converting voltage output to noise levels. This manual is written in Chinese.
| Noise measurement range | 30~130 dB |
|---|---|
| Noise measurement accuracy | ±3% |
| Output method | RS485/TTL/DC0‑3V |
| Power supply | DC5V 1A |
| Operating temperature | -40~80°C |
| Operating humidity | 5%RH~90%RH |
Send the Modbus query frame "FA 03 00 66 00 01 71 9E"; the device will respond with the current address in the first byte.
Use the write command "01 06 00 67 00 05 F8 16" to set the baud‑rate register to code 5, which corresponds to 38400 bps.
Send a write command such as "01 06 00 6B 00 64 F9 FD" where the data field (e.g., 0x64) is the desired calibration offset.