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    pH Controller for Water/Food Process

    The pH controller transmits the standard output signal 4-20mA to the digital panel meter/VFD/PLC/logger, or transmits the RS485 signal to the computer for remote monitoring and recording, which is widely used in the test of water/food pH or ORP value and monitoring.
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    🔙 30-day returns
    📅 Delivery: 7-12 days

    The digital pH meter can be used in conjunction with various pH electrodes or ORP electrodes to realize on-line continuous testing and monitoring of sewage, corrosive solutions, liquid medicines, beer, drinking water, food, and high-temperature disinfection occasions.

    pH notation structure

    Watchdog protection system, strong anti-interference ability

    • 2.4 inch LCD display.
    • Good anti-interference performance.
    • Manual/automatic temperature compensation.
    • User settings: Language, buzzer, LCD backlight, password, pH/ORP.
    • electrode, manual/automatic temperature compensation, pH/ORP calibration, pH/ORP/temperature modification, pH/ORP high/low alarm, output signal 4-20mA and RS485, etc.
    • Internal industrial watchdog insures pH meter doesn't crash.



    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.

    pH meter applications

    Model SISCO-PHCR-PH6
    Weight 1kg
    Dimension 100*100*150mm (H*W*D) with hole size 93*93mm
    Measuring range pH: 0~14pH, ORP: -1000~1000mV (-2000~2000mV need customization)
    Accuracy ±0.02pH, ±1mV
    Resolution ±0.01pH, ±1mV
    Stability ≤0.02pH/24h, ≤3mV/24h
    Input impedance ≥10^12Ω
    Temperature range -10~+130℃ (NTC 10K or PT1000, accuracy: ±0.5℃)
    Temperature compensation -10~+130℃ manual/automatic
    Output signal * Isolated 4-20mA signal (error: ±0.1%, under maximum loop resistance 750Ω)
    Communication function * RS485 with standard MODBUS-RTU (Now RS485 software is free.)
    Power supply AC 220V±10%, 50Hz/60Hz
    Alarm relay 2 alarm relays: AC 250V/3A
    Function: high alarm, low alarm

    The pH meter and pH/ORP electrode selection

    pH meter pH/ORP electrode Industry Temperature range Advantage
    SISCO-PHCR-PH160 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:

    pH controller wiring diagram

    Definition of the ports

    pH controller ports definition

    • INPUT: Measuring terminal of the electrode
    • REF: Reference terminal of the electrode
    • NC: Undefined
    • A: Temperature compensation terminal A, connect to NTC 10K or PT1000
    • B: Temperature compensation terminal B, connect to NTC 10K or PT1000
    • C: Temperature compensation terminal C, connect to 3-wire PT1000 GND (3-wire PT1000), or connect to B (2-wire PT1000), or NC (NTC 10K)
    • RS485 (A+): RS485 communication interface A+
    • RS485 (B-): RS485 communication interface B-
    • 4-20mA (+): 4-20mA output terminal +
    • 4-20mA (-): 4-20mA output terminal -
    • AC 220V/110V (L) or DC 24V (-): AC 220V/110V live wire or DC 24V (-)
    • AC 220V/110V (N) or DC 24V (+): AC 220V/110V neutral wire or DC 24V (+)
    • HO: Normally-open relay for high alarm
    • HC: Normally-closed relay for high alarm
    • LO: Normally-open relay for low alarm
    • LC: Normally-closed relay for low alarm
    • COM: Common terminal


    RS485 communication data and register address as follows:

    Address Data type Function code Explanation Access right
    0x0000 unsigned short 0x03 pH value (default in two decimals) Read only
    0x0001 unsigned short 0x03 Temperature value (default in one decimals) Read only
    0x0002 short 0x03 ORP value (signed integer) Read only

    Q1: What is the working principle of a pH meter?
    A1: The pH meter works on the principle of a galvanic battery. The electromotive force between the two electrodes of the galvanic battery is based on Nernst's law, which is not only related to the properties of the electrodes, but also to the concentration of hydrogen ions in the solution. There is a the corresponding relationship between the electromotive force of the primary cell and the hydrogen ion concentration, and the negative logarithm of the hydrogen ion concentration is the pH value.

    Q2: The same sample is measured on two pH meters at the same time, why are the readings inconsistent?
    A2: Because the calibration conditions of the two pH meters are different (such as calibration done at different times), the measured values are different. Therefore, the pH meter should be calibrated at the same time with the same buffer, and then measured at the same time.

    Q3: How do I know if the pH meter is accurate?
    A3: Take three standard buffer solutions: pH 6.86, pH 4.00, pH 9.18 (preferably freshly prepared and at the same temperature), position calibration at pH 6.86, slope calibration at pH 4.00, and then test pH 9.18 to know the pH meter Is it accurate.

    Tips: What is a two-point calibration of a pH meter?

    For precision pH meters, in addition to "positioning" and "temperature compensation" adjustment, there is also an electrode "slope" adjustment, which requires two standard buffers for calibration. Generally, the "positioning" calibration is carried out at pH 6.86 or pH 7.00, and then according to the acid-base condition of the test solution, pH 4.00 (acidic) or pH 9.18 or pH 10.01 (alkaline) buffer solution is used for "slope correction. The specific operation steps are as follows:

    1. The electrode is washed and dried, immersed in a pH 6.86 or pH 7.00 standard solution, and the temperature compensation knob is placed at the solution temperature. After the displayed value is stable, adjust the positioning knob so that the displayed value of the instrument is the pH value of the standard solution.
    2. Take out the electrode, wash it, spin dry, and immerse it in the second standard solution.
    3. After the displayed value is stable, adjust the slope knob of the instrument so that the displayed value of the instrument is the pH value of the second standard solution.
    4. The electrode is washed and dried, and then immersed in the standard solution of pH 6.86 or pH 7.00. If the error exceeds 0.02 pH, repeat steps 1 and 2. Until the two standard solutions do not need the adjustment knob to display the correct pH value.
    5. Take out the electrode, wash it and spin it dry, adjust the pH temperature compensation knob to the sample temperature, immerse the electrode in the sample solution, shake it and place it at rest, and display a stable reading.

    Thank you for buying industrial test and measurement equipment on, all products sold by SISCO and the partner cover a 12 months warranty, effective from the date of receiving the products.

    What is covered?

    SISCO is responsible for providing free spare parts, and free technical support to assist the customer to repair the defective products until the problem is solved.

    What is not covered?

    • Product purchased from anyone other than a SISCO store or a SISCO authorized reseller.
    • Expendable parts.
    • Routine cleaning or normal cosmetic and mechanical wear.
    • Damage from misuse, abuse or neglect.
    • Damage from use of parts other than SISCO approved.
    • Damage from use outside the product’s usage or storage parameters.
    • Damage from use of parts not sold by SISCO.
    • Damage from modification or incorporation into other products.
    • Damage from repair or replacement of warranted parts by a service provider other than a SISCO authorized service provider.
    • Damage caused by the application environment not meeting the product usage requirements and the failure to perform preventive maintenance.
    5.0 2
    Write your own review Close
    Magnus | 11/26/2023 10:44 PM
    Ideal for food processing
    I am the owner of a small food processing plant and purchased this pH controller and it meets my needs perfectly. It is very accurate in controlling the pH level of the food treatment process and ensures the consistency and quality of our products. The user interface is user friendly and easy to use even for those with limited technical knowledge.
    Jarren | 2/28/2023 5:21 PM
    A pH meter that offers great value for money
    Digital pH meters have always been a reliable tool in my laboratory work. The automatic temperature compensation feature saves a lot of time and ensures accuracy. The compact size makes it easy to carry and use The long battery life means I don't have to worry about it running out of power during long experiments.