The SX721 is a handheld pH/ORP meter designed for high‑accuracy water analysis in field and laboratory settings. It combines a microprocessor, dual‑parameter sensors and a back‑lit LCD to provide pH, ORP and temperature readings.
The manual covers safety information, device overview, technical specifications, step‑by‑step pH and ORP measurement procedures, parameter configuration, data storage, and warranty details, helping users set up, calibrate and maintain the instrument correctly. This manual is written in Chinese.
| pH measurement range | -2.00 ~ 19.99 pH |
|---|---|
| pH resolution | 0.1/0.01 pH |
| pH accuracy (electrode) | ±0.01 pH |
| pH accuracy (solution) | ±0.02 pH |
| Input current | ≤2×10⁻¹² A |
| Input impedance | ≥1×10¹² Ω |
| Stability | ±0.01 pH/3h |
| Temperature compensation range | 0 ~ 100 °C (auto) |
| ORP measurement range | -1999 mV ~ 0 ~ 1999 mV |
| ORP resolution | 1 mV |
| ORP accuracy (electrode) | ±0.1 % FS |
| ORP accuracy (solution) | ±15 mV |
| Data storage capacity | 200 groups |
| Power source | 2× AA 1.5 V batteries |
| Instrument dimensions | 65 × 120 × 31 mm |
| Instrument weight | 180 g |
| IP rating | IP57 |
| Operating temperature | 5 ~ 35 °C |
| Operating humidity | ≤85 % |
The instrument can store up to 200 groups of data (100 pH and 100 ORP measurements).
It is powered by two AA batteries (1.5 V each).
The meter is rated IP57 for dust and water protection.