The VMS VMS-300B-PH-N01-201 user manual provides product overview, hardware connection, operation, calibration, alarm settings, communication protocol, and…
This manual introduces the VMS VMS-300B-PH-N01-201 pH transmitter, describing its high‑precision AD conversion, temperature compensation, RS485 MODBUS‑RTU communication, and built‑in watchdog. It outlines the main features, measurement ranges, and typical applications such as power plants, chemical, and water treatment.
The document details hardware installation, wiring, menu operation, electrode and ORP calibration procedures, alarm and hysteresis configuration, communication settings, and safety/maintenance guidelines. It also includes register addresses for Modbus communication and troubleshooting advice. This manual is written in Chinese.
| pH measurement range | 0–14.00 pH |
|---|---|
| pH measurement accuracy | ±0.02 pH |
| ORP measurement range | -1999 to +1999 mV |
| ORP measurement accuracy | ±1 mV |
| Temperature measurement range | 0–99.9 °C (max -10–120 °C) |
| Temperature measurement accuracy | ±0.5 °C |
| Input impedance | ≥10^12 Ω |
| Output current | 4–20 mA |
| Power supply | AC220V±22V, 50±1 Hz (optional DC24V) |
| Protection rating | IP54 |
| Dimensions | 96 × 96 × 110 mm |
| Weight | 0.8 kg |
| Communication interface | RS485 MODBUS‑RTU |
Use the menu items 1 and 2 to set the high‑alarm and low‑alarm values; the allowed range is –20.00 to 20.00 pH.
The device supports RS485 communication using the MODBUS‑RTU protocol, with configurable baud rate (default 4800 bit/s).