Description
Digital pH meter is an intelligent industrial online pH controller for testing/monitoring/recording water or food pH value, ORP value and temperature value.
Application:
Digital pH/ORP meter is widely used in the continuous testing and monitoring of pH, ORP and temperature in thermal power, chemical fertilizer, metallurgy, environmental protection, pharmaceutical, biochemical, food, drinking water, etc.
Function:
- 4.3 inch LCD display
- Good anti-interference performance
- Manual/automatic temperature compensation
- User settings: Buzzer, LCD backlight, password, pH/ORP electrode, manual/automatic temperature compensation, pH/ORP calibration, pH/ORP modification, pH/ORP high/low alarm, output signal 4-20mA and RS485, etc.
- Data record function
- Automatic cleaning function
Specification:
| Model | ATO-PHCR-PH8.5 |
| Weight | 1kg |
| Dimension | 144*144*115mm (H*W*D) with hole size 138*138mm |
| Display | 4.3 inch LCD color screen |
| Measuring range | pH/Antimony: -2.00 ~ +16.00pH ORP: -2000 ~ +2000mV Temperature: -10.0 ~ +130.0℃ |
| Accuracy | pH:±0.02pH Antimony: ±0.2pH |
| ORP: ±2mV | |
| Temperature: NTC10K: ±0.3℃ (-10~+60℃), ±2.0℃ (60~130℃) PT1000/PT100: ±0.3℃ |
|
| Input impedance | ≥1012Ω |
| Resolution | pH/Antimony: 0.01pH |
| ORP: 1mV | |
| Temperature range | 0~100℃ (NTC 10K, accuracy: ±0.5℃) |
| Repeatability | 0.02pH |
| Temperature compensation | Compensation mode: Manual/Automatic |
| Compensation curve: Linear, Acid, Base, Pure | |
| Record | 100 sets, recording interval can be set through configuration, the recording method is FIFO. |
| Output signal * | Isolated 4-20mA signal (error: ±0.2%, under maximum loop resistance 750Ω), default 1 * 4-20mA output, optional 2 * 4-20mA outputs |
| Communication function | RS485 with standard MODBUS-RTU (Now RS485 software is free.) |
| Power supply | AC: 85~265V, 50Hz/60Hz |
| DC: 21.6~26.4V | |
| Alarm relay delay | 0~9999 seconds, adjustable |
| Protection class | IP66 |
| Operating temperature | Temperature: 0~60℃ |
| Relative Humidity: 10~85%RH (no condensing) | |
| Storage condition | Temperature: -15~+65℃ Relative Humidity: 5~95%RH (no condensing) |
| Automatic cleaning * | Manually clean, set cleaning interval |
The pH meter and pH/ORP electrode selection:
| pH meter | pH/ORP electrode | Industry | Temperature range | Advantage |
| ATO-PHCR-PH8.0 | Combination pH electrode | Sewage disposal | 0-60℃ (32-140℉) | Combination electrode has automatic temperature compensation function, suitable for occasions with large temperature fluctuations. |
| Pure water pH electrode | Drinking water | 0-60℃ (32-140℉) | The pH calomel electrode can be used in strong acid or alkali. | |
| PTFE pH electrode | Chemical | 0-60℃ (32-140℉) | The electrode shell is made of PTFE, suitable for corrosive solution (strong acid or alkali), has longer life in harsh environments. | |
| pH glass electrode | Sewage disposal / food | 0-95℃ (32-203℉) | Direct lead, double-layer glasses. | |
| Desulfurization pH electrode | Desulfurization | 0-60℃ (32-140℉) | Flat electrode, strong anti-pollution ability and longer life | |
| High temperature/sterilization pH electrode | Food | 0-130℃ (32-266℉) | The electrode can withstand high temperature of 0-130℃, suitable for occasions of high temperature sterilization in pharmaceutical factories, breweries, etc. | |
| High pressure/accuracy pH electrode | Laboratory | 0-80℃ (32-176℉) | Its linearity and accuracy are higher than all above electrodes. |
Wiring diagram:
Definition of the ports:
- INPUT: Measuring terminal of the pH/ORP/Antimony electrode
- NC: Undefined
- REF: Reference terminal of the pH/ORP/Antimony electrode
- NC: Undefined
- TEMPA: Temperature compensation terminal A
- TEMPB: Temperature compensation terminal B
- TEMPC: Temperature compensation terminal C
- RS485 (A+): RS485 communication interface A+
- RS485 (B-): RS485 communication interface B-
- 0/4-20mA (A+): A current output terminal +
- 0/4-20mA (A/B-): A/B current output terminal –
- 0/4-20mA (B+): B current output terminal +
- WASH: Cleaning device relay
- WASH: Cleaning device relay
- REL B: Alarm relay B
- REL B: Alarm relay B
- REL A: Alarm relay A
- REL A: Alarm relay A
- POWER N: AC 220V/110V neutral wire
- POWER L: AC 220V/110V live wire
Communication:
RS485 communication data and register address as follows:
| Address | Access authority | Data type | Data type | Function code | Explanation |
| 0x0001 | Read only | Float | 4 | 0x03 | pH/ORP/Antimony electrode measurement value |
| 0x0003 | Read only | Float | 4 | 0x03 | Temperature measurement value |
Tips: How to control the pH value to be 6-9 with a pH meter?
The pH electrode with submersible installation is submerged in the alkali pool to test the pH value. The lower limit alarm relay of the pH meter is connected to a solenoid valve (normally closed solenoid valve).
First, set the lower alarm value to be 6 for closed and 7 for open, when the pH value is below 6, the alarm relay is closed and the dosing pump works to add lye to the pool. When pH value in the pool reaches 7, the alarm relay is closed, and the dosing pump stops to add lye.
Second, set the upper alarm value to be 9 for closed and 8 for open, when the pH value is above 9, the alarm relay is closed and the dosing pump works to add acid liquor to the pool. When pH value in the pool reaches 8, the alarm relay is close and the dosing pump stops to add acid liquor.
Through the alarm return difference, pH value will be controlled between 6 and 9.
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