Technical Parameters 1. Measurement Range: pH -4.00~18.00pH ORP -1999~+1999mV 2. Resolution: 0.01 pH; 1mV 3. Accuracy: 0.05pH; 1mV 4. Stability: ≤0.02pH/24h; ≤1mV/24h 5. pH Calibration Range: Zero Point ±1.45 pH, Slope ±30% 6. pH Standard Solution: 6.86/4.00/9.18 or 7.00/4.01/10.00 7. ORP Standard Solution: Any standard solution 8. Control Range: 0~14.00pH; -1999~+1999mV 9. Output Signal: 4~20mA output 10. Control Output Method: ON/OFF relay output contact 11. Operating Voltage: 220VAC±10%, 50/60Hz 12. Dimensions: 96×96×115 mm 13. Relay Load Capacity: Max AC220V 5A 14. Current Output Load: Maximum allowable load 500Ω 15. Signal Input Impedance: ≥1×1012Ω 16. Instrument Operating Conditions: ① Ambient Temperature: -5 ~ 55℃ ② Relative Humidity: ≤90% ③ No strong magnetic field interference except for the Earth's magnetic field