YOKOGAWA FU24 pH/ORP Composite Sensor with Pressure Compensation (IM 12B06J03-03EN-P)

Remove the 'wet pocket' and rinse the measuring end with deionized water to avoid residual protective solution affecting the measurement; It is recommended to recalibrate before first use (factory calibration data can be found in the QIC certificate).

2. Installation steps

(1) Installation method

Support pipeline installation, immersion installation, and bypass circuit installation. The core steps are as follows:

Thread sealing: Wrap polytetrafluoroethylene tape around the 1-inch NPT thread end (to avoid covering the thread end and prevent contamination of the medium);

Fixed sensor: Use a wrench to clamp onto the flat surface of the sensor body and tighten with a maximum torque of 7.5 Nm to avoid over tightening and damaging the threads;

Angle adaptation: It can be installed at any angle (including inversion), and it is recommended that the medium flow direction be towards the measuring end to reduce bubble adhesion.

(2) Wiring specifications

According to the differences in models, the wiring methods are divided into two categories: fixed cables and Vario Pin connectors:

Wiring Type Wiring Requirements

Fixed cable - brown (core wire): pH signal;

-Brown (shielding layer): pH shielding;

-Black: reference electrode;

-Yellow: LE/ORP signal;

-Red/Blue: Pt1000 temperature sensor;

-The shielding layer needs to be grounded at one end (transmitter side) to avoid interference;

Vario Pin Connector - VP Type (No ID Chip): 8-pin interface, A-pH, B-reference, C-pH shielded D-LE/ORP、E/F-Pt1000；

-VS type (with ID chip): additional G-ID chip power supply, H-ID chip data, requires SA11-P1 adapter;

Calibration and maintenance

1. Calibration process

(1) PH calibration (two-point calibration method)

IEC standard buffer solutions (pH 4.01, 6.87, 9.18) are required, and the steps are as follows:

Cleaning the sensor: Soak it in a 5% hydrochloric acid solution for 5 minutes to remove surface dirt, and then rinse it clean with deionized water;

The first point of calibration: immerse the sensor in pH 6.87 buffer solution, wait for the reading to stabilize, and then perform "zero calibration" according to the transmitter manual;

Second point calibration: Select a buffer solution based on the pH range of the process (4.01 for acidity and 9.18 for alkalinity), repeat step 2 to perform "slope calibration";

Verification and reset: After calibration, rinse with deionized water and immerse in buffer solution again to verify that the error is ≤ 0.02 pH. After confirmation, reinstall the process pipeline.

(2) ORP/rH calibration

Use Chinhydron standard solution (1g/200mL buffer), core steps:

Choose a buffer solution with a pH close to the process pH (such as pH 4.01 or 6.87), dissolve the quinone hydroquinone powder until saturated;

Immerse the sensor in a standard solution, wait for the reading to stabilize, and manually input the theoretical value according to the transmitter manual (such as ORP=96 mV, rH=23.6 at pH 6.87);

The calibration error should be ≤ ± 10 mV, otherwise the ORP electrode needs to be cleaned (wipe the platinum surface with a soft cloth) and recalibrated.

2. Daily maintenance

(1) Regular cleaning

Choose a cleaning solution based on the type of medium contamination, only clean the measuring end (to avoid damaging the cable/connector):

Scale/Hydroxide: Soak in 5% hydrochloric acid for 10 minutes and rinse with deionized water;

Oil stains/organic matter: Clean with hot water and neutral detergent. Stubborn stains can be gently wiped with a small amount of calcium carbonate powder;

Protein residue: Soak in hydrochloric acid solution containing gastric protease (10g gastric protease+8.5mL concentrated hydrochloric acid/1L water) for 30 minutes;

Reference end blockage: Immerse the sensor in 3M KCl solution at 70 ℃, cool naturally to room temperature, and restore the conductivity of the reference junction.

(2) Replacement of vulnerable parts

O-ring/bellows: Check every 6-12 months. If aging or cracking occurs, replace with Viton material spare parts to avoid leakage;

Cable/connector: If damaged, replace the original WU10/WE10 cable to ensure that the explosion-proof performance is not compromised.

Troubleshooting and spare parts

1. Common faults and solutions

Possible causes and solutions for the fault phenomenon

PH reading drift is large. 1. Reference junction blockage; 2. Electrode contamination; 3. The buffer solution has expired; 1. Use 3M KCl solution to regenerate the reference end; 2. Clean the electrodes according to the type of medium; 3. Replace with fresh buffer solution;

ORP reading unresponsive 1. Platinum electrode surface oxidation; 2. Poor cable contact; 3. The medium has no redox activity; 1. Gently sand the platinum surface with sandpaper; 2. Check if the cable wiring is loose; 3. Confirm whether the process medium is suitable for ORP measurement;

Abnormal temperature reading: 1. Pt1000 cable open circuit; 2. The temperature compensation setting of the transmitter is incorrect; 1. Use a multimeter to measure the resistance of Pt1000 (approximately 1000 Ω at 25 ℃), and replace the cable if there is a circuit break; 2. Confirm that the temperature sensor type of the transmitter is Pt1000;