| U-51 | U-52 | U-52G | U-53 | U-53G | ||
| Sensor Probe | Measurement temperature | −10 to 55℃ | ||||
| Maximum sensor diameter | Approx. 96 mm | |||||
| Probe length | Approx. 340 mm | |||||
| Cable length | Standard: 2 m, option: 10, 30 m | |||||
| Mass | Approx. 1,800 g (Approx. 3.97 lbs) | |||||
| Automatic calibration (uses pH4) | ● | |||||
| Turbidity wiper | — | — | — | ● | ● | |
| Measurement depth | Max. 30 m | |||||
| Liquid contact part material (liquid end material) | PPS, glass, SUS316L, SUS304, FKM, PEEK,Q, titanium, FEP membrane, POM | |||||
| Water resistance | JIS protection level 8 | |||||
| Control Unit | Outer dimensions | 115 (W) × 66 (D) × 283 (H) mm | ||||
| Mass | Approx. 800 g (approx. 1.76 lb) | |||||
| LCD | 320 × 240 liquid crystal display; backlit, black and white | |||||
| Data memory | 10,000 | |||||
| Communication | USB | |||||
| Battery | C batteries x 4 | |||||
| Water resistance | JIS protection level 7 (when sensor cable is fitted) | |||||
| Battery Life | Approx. 70 hours (without backlight) | Approx. 500 measurements | ||||
| Storage temperature | −10 to 60℃ | |||||
| Ambient temperature | −5 to 45℃ | |||||
| pH ●Two-point calibration ●Automatic temperature | Measurement principle | Glass electrode method | ||||
| Range | pH0 to 14 | |||||
| Resolution | 0.01 pH | |||||
| Repeatability | ±0.05 pH | |||||
| Accuracy | ±0.1 pH | |||||
| Oxidation Reduction Potential (ORP) | Measurement principle | Platinum electrode method | ||||
| Range | −2000 mV~+2000 mV | |||||
| Resolution | 1 mV | |||||
| Repeatability | ±5 mV | |||||
| Accuracy | ±15 mV | |||||
| Dissolved Oxygen (DO) ●Salinity conversion (0 to 70 PPT/automatic) ●Automatic temperature compensation | Measurement principle | Polarographic method | ||||
| Range | 0 to 50.0 mg/L | |||||
| Resolution | 0.01 mg/L | |||||
| Repeatability | ±0.1 mg/L | |||||
| Accuracy | 0 to 20 mg/L: ±0.2 mg/L 20 to 50 mg/L: ±0.5 mg/L | |||||
| Conductivity (COND) ●Auto range ●Automatic temperature conversion (25℃) | Measurement principle | 4 AC electrode method | ||||
| Range | 0 to 10 S/m (0 to 100 mS/cm) | |||||
| Resolution | 0.000 to 0.999 mS/cm: 0.001 mS/cm 1.00 to 9.99 mS/cm: 0.01 mS/cm 10.0 to 99.9 mS/cm: 0.1 mS/cm | |||||
| Repeatability | 0.0 to 99.9 mS/m: 0.1 mS/m 0.100 to 0.999 S/m: 0.001 S/m 1.00 to 9.99 S/m : 0.01 S/m | |||||
| Accuracy | *±1% F.S. (Median of two-point calibration) | |||||
| Salinity | Measurement principle | Conductivity conversion | ||||
| Range | 0 to 70 PPT (permillage) | |||||
| Resolution | 0.1 PPT | |||||
| Repeatability | ±1 PPT | |||||
| Accuracy | ±3 PPT | |||||
| Total Dissolved Solid (TDS) ●Conversion factor setting | Measurement principle | Conductivity conversion | ||||
| Range | 0 to 100 g/L | |||||
| Resolution | 0.1 % F.S. | |||||
| Repeatability | ±2 g/L | |||||
| Accuracy | ±5 g/L | |||||
| Seawater specific gravity ●Display σt, σ0, σ15 | Measurement principle | Conductivity conversion | ||||
| Range | 0 to 50σt | |||||
| Resolution | 0.1 σt | |||||
| Repeatability | ±2 σt | |||||
| Accuracy | ±5 σt | |||||
| Temperature | Measurement principle | Thermistor method | ||||
| Range | −10 to 55℃ | |||||
| Resolution | 0.01 ℃ | |||||
| Repeatability | *±0.10℃ (at calibration point) | |||||
| Accuracy | JIS class B platinum thermometer sensor (±0.3+0.005 | t |) | |||||
| Turbidity (TURB) | Measurement principle | — | LED light source and 30°scattering method | Tungsten lamp source and 90°scattering method | ||
| Range | 0 to 800 NTU | 0 to 1000 NTU | ||||
| Resolution | 0 to 99.9 NTU: 0.1 NTU 100 to 800 NTU: 1 NTU | 0 to 9.99 NTU: 0.01 NTU 10 to 99.9 NTU: 0.1 NTU 100 to 1000 NTU: 1 NTU | ||||
| Repeatability | *±5% (Reading) or ± 0.5 NTU whichever is greater | ±3% (Reading) or ±0.1 NTU whichever is greater | ||||
| Accuracy | ±5% (Reading) or ±1 NTU whichever is greater | 0 to 10 NTU: ±0.5 NTU 10 to 1000 NTU: 3% (Reading) or ±1 NTU whichever is greater | ||||
| Water depth | Measurement principle | — | — | Pressure method | ||
| Range | 0 to 30 m | |||||
| Resolution | 0.05 m | |||||
| Repeatability | ±1 % F.S. | |||||
| Accuracy | ±0.3 m | |||||
| GPS | 12 channel parallel | — | — | ● | — | ● |
Note:
* Battery life based on continuous operation using alkaline C dry batteries when the monitor temperature is over 20℃ and the backlight OFF.
* Accuracy is measured by calibrating 4 points for turbidity and electrical conductivity and 2 points for all other measurements against standard solution.
* Repeatability is measured by the ability to reproduce the results against the standard solution (at 25℃ normal pressure condition).























































































































