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    Digital pH Meter, Online Test pH/ORP of Water/Food

    5 out of 5 based on 5 reviews | Write a review
    Digital pH/ORP meter can be used with various pH electrodes or ORP electrodes to realize online testing and monitoring of pH (-2~+16) / ORP (-1999~+1999mV) / temperature (-10~+130℃/14~266℉) of sewage, corrosive solution, liquid medicine, beer, drinking water, food, etc. Online pH meter can be connected to digital panel meter/VFD/PLC/recorder (4-20mA output), or connected to computer for remote monitoring and recording (RS485 communication). Digital pH meter can also be connected with alarm relays and solenoid valves to form a simple pH process control system.
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    Delivery date: 6-12 days

    Digital pH meter is an intelligent industrial online pH controller for testing/monitoring/recording water or food pH value, ORP value and temperature value.

    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.


    • 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


    Model ATO-PHCR-PH8.0
    Weight 1kg
    Dimension 144*144*115mm (H*W*D) with hole size 138*138mm
    Display 4.3 inch LCD color screen
    Measuring range pH: -2.00 ~ +16.00pH
    ORP: -1999 ~ +1999mV
    Temperature: -10.0 ~ +130.0℃
    Accuracy pH:
    pH sensor: ±0.02pH
    Antimony pH sensor: ±0.2pH
    ORP: ±0.1%FS
    NTC10K: ±0.3℃ (-10~+60℃), ±2.0℃ (60~130℃)
    PT1000/PT100: ±0.3℃
    Input impedance ≥10^12Ω
    Temperature range 0~100℃ (NTC 10K, accuracy: ±0.5℃)
    Temperature compensation NTC10K/PT1000, manual/automatic
    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 100~240V, 50Hz/60Hz, 5W Max.
    Alarm relay 2 alarm relays: AC 245V/5A Max., NO
    Function: high alarm, low alarm
    Protection class IP65
    Operating temperature 0~60℃
    Storage condition Temperature: -20~+70℃
    Humidity: 10~85%RH (No condensation)
    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:
    Digital online water/food pH/ORP meter wiring diagram
    Definition of the ports:

    1. INPUT: Measuring terminal of the pH/ORP/Antimony electrode
    2. NC: Undefined
    3. REF: Reference terminal of the pH/ORP/Antimony electrode
    4. NC: Undefined
    5. TEMPA: Temperature compensation terminal A
    6. TEMPB: Temperature compensation terminal B
    7. TEMPC: Temperature compensation terminal C
    8. RS485 (A+): RS485 communication interface A+
    9. RS485 (B-): RS485 communication interface B-
    10. 0/4-20mA (A+): A current output terminal +
    11. 0/4-20mA (A/B-): A/B current output terminal -
    12. 0/4-20mA (B+): B current output terminal +
    13. WASH: Cleaning device relay
    14. WASH: Cleaning device relay
    15. REL B: Alarm relay B
    16. REL B: Alarm relay B
    17. REL A: Alarm relay A
    18. REL A: Alarm relay A
    19. POWER N: AC 220V/110V neutral wire
    20. POWER L: AC 220V/110V live wire

    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.

    Existing reviews of Digital pH Meter, Online Test pH/ORP of Water/Food
    Consult for the PH devices
    I’m and engineer consultant with Exponent and I have a client who is interested in some of ATO’s products. Overall, my client is looking for a system to track pH in a residential drinking water pipe (1 to 1.5 in). Conceptually, the pH probe will be located inside the pipe and pH measurements should be taken every 6 to 10 minutes. The pH data will be transmitted to a digital meter that should contain a recorder (memory card) to save the data. The system must have an easy operation that allows for probe calibration.

    I believe ATO’s Digital pH Meter and ATO’s pH electrode for Pure Water are suitable for the job. As an advisor to the client, I would appreciate clarifications to the questions below.

    Questions about the system:
    Does your company provide one compiled system where the digital meter and the pH probe are all one piece instead of two different parts?

    What is the electricity demand of the system (e.g. probe and digital meter)?
    Do you provide a system where the data is transmitted remotely instead of having a memory stick?

    Questions about installation:
    Does your company provide a fitting (mounts) to the pipe where the probe will be located? Can the probe be easily removed for cleaning/calibration purposes?
    How are the connection between the digital meter and the pH probe?
    How far apart can the probe be from the digital meter?

    Questions about maintenance:
    How often does the pH probe needs to be calibrated? How often do they have to be cleaned?
    How fast will the memory stick be filled up?

    Thank you and I look forward to hearing back from you.
    From: Noah | Date: 05/02/2024
    Was this review helpful? Yes No (0/0)
    ATO Responded
    1. We can Not provide compiled systems, the digital meter and pH probe are both separate and are different components.

    2. The power supply of the probe and digital instrument is 220V or 24V.

    3. For remote data, you can use 485 or analog.

    4. It can be equipped with a threaded base and is easy to disassemble.

    5. The digital meter and pH probe are screwed together.

    6. The distance between the probe and the digital instrument can be connected through a cable, and the longest distance does not exceed 40 meters.

    7. The frequency of calibration depends on the water quality, usually once a month.

    8. The memory module will be filled up depending on how long it is set, and it will be displayed on the meter.
    Some questions about the pH meter
    1.I would like to know the type of controller they refer to according to the pH meter that was purchased.
    2. I would also like to know how I can test the pH meter with a multimeter to verify that it is working correctly.
    From: lily | Date: 04/09/2023
    Was this review helpful? Yes No (0/0)
    ATO Responded
    Unfortunately, you can Not test the pH meter with a multimeter to verify that it is working correctly, only with standard solutions. You can refer to the user manual of the attached pH meter.
    Can this pH meter be use for PH and ORP?
    When I check from the website, Digital pH/ORP meter can be used with various pH electrodes or ORP electrodes to realize online testing and monitoring of pH (-2~16) / ORP (-1999~1999mV) / temperature (-10~130℃/14~266℉)…
    the expression says that this model can use for PH and ORP.
    Is this right or is it used only for PH measurement?
    I am confused, please inform me.
    From: landon | Date: 31/07/2023
    Was this review helpful? Yes No (0/0)
    ATO Responded
    We confirm that this model can use for PH and ORP, and the Digital pH/ORP meter is generally generic.
    Online pH meter
    Dear Sir,
    Please recommend an online pH meter, with accessory/electrode for continuous testing tape water.  Please quote CIP Hong Kong.  thanks Terrence.
    From: Terrence | Date: 30/03/2021
    Was this review helpful? Yes No (0/0)
    ATO Responded
    We recommend this digital pH meter with SKU ATO-PHCON-PH160, and its corresponding product link You can click on the product link to see the details.
    The measured data of pH meter is very close to the theoretical value.
    Digital pH meter is very practical and convenient to carry to other place. The pH meter has high accuracy. The measured data is very close to the theoretical value.
    From: Kraus | Date: 20/10/2018
    Was this review helpful? Yes No (0/0)
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