TCML 412 N TCML 412 M12-2 Sensor for Total Chlorine

1 Overview

The TCML 412 N and TCML 412 M12-2 are membrane-covered, amperometric sensors designed for the determination of total chlorine in water. They utilize a potentiostatic three-electrode system with integrated measuring electronics, delivering a temperature-compensated signal. A zero-point adjustment is not required. Routine calibration is performed by comparison with the photometric DPD method according to DIN 38408.

The TCML 412 N sensor connects to monitors via a two-line connection, providing power and transmitting a 4-20 mA current signal. The TCML 412 M12-2 sensor features a four-pin socket for connection to monitors like the CL 7010 via an ADA Cl/IDS cable, transmitting a 0 to -1500 mV voltage signal.

Structure of TCML 412 M12:

The sensor consists of a shaft, M12 flange plug (on M12-2 model) or Pg7 screwed connection (on N model), sensor element, counter electrode, O-ring, reference electrode, measurement electrode, valve opening, membrane cap, and membrane holder.

2 Safety Instructions

This operating manual contains important safety information. Always read and understand the manual before operating the product. Safety instructions are highlighted with a warning symbol (triangle).

2.1 Safety Information

• WARNING: Indicates a potentially dangerous situation that could lead to serious injury or death if safety instructions are not followed.
• CAUTION: Indicates a potentially dangerous situation that could lead to slight injury if safety instructions are not followed.
• NOTE: Indicates a situation where damage to goods may occur if actions are not taken.

Observe all labels, information signs, and safety symbols on the product. Further safety information can be found in the operating manuals of other components and safety datasheets of calibration and maintenance equipment.

2.2 Safe Operation

• Authorized Use: Stationary measurement of total chlorine in drinking water, swimming pool water, and process water. Operation must strictly follow this manual.
• Requirements for Safe Operation: Operate only as authorized, use only specified energy sources and environmental conditions, and do not open the product.
• Unauthorized Use: Do not operate if visibly damaged or stored under adverse conditions.

3 Commissioning

3.1 Scope of Delivery

The scope of delivery includes the sensor (TCML 412 N or TCML 412 M12-2), a dropping bottle with electrolyte solution, a polishing strip, and this operating manual.

3.2 Filling the Membrane Cap with Electrolyte Solution

NOTE: Improper handling can damage the sensor. Do not touch the electrode finger or apply pressure to the membrane disk. Do not unscrew the membrane holder.

1. Unscrew the membrane cap from the electrode shaft.
2. Fill the membrane cap completely with electrolyte solution, ensuring no bubbles are present.
3. Lift the hose ring to expose the valve opening. Hold the sensor shaft upright and place it on the filled membrane cap, allowing excess electrolyte to escape. Screw the electrode shaft into the membrane cap slowly, ensuring no gap remains and no back pressure develops.
4. Slide the hose ring over the valve opening and into the groove.
5. Rinse off any adhering electrolyte solution.

3.3 Electrical Connection

Refer to the operating manual of the respective measuring transmitter or MIQ/IDS module for detailed connection instructions for the TCML 412 N and TCML 412 M12-2 sensors.

3.4 Installation in the Flow-Through Vessel D-CL

The D-CL vessel is optimized for the TCML 412 N. Position the sensor carefully for optimal measuring function.

1. Slide the black O-ring and then the PVC sliding ring over the sensor.
2. Unscrew the screw connection of the flow-through vessel.
3. Insert the sensor into the vessel without the cable connected.
4. Slide the screw connection over the sensor and screw it onto the vessel.
5. Reconnect the sensor connection cable.

NOTE: Open the feed slowly during commissioning to prevent damage from shock pressure.

3.5 Installation in the Flow-Through Vessel D 19

The D 19 vessel is optimized for the TCML 412 M12-2. A marking on the sensor shaft indicates the optimal installation position.

1. Insert the black O-ring and PVC slide ring into the 1" installation opening of the flow-through vessel.
2. Push the coupling ring loosely onto the sensor.
3. Insert the sensor with the coupling ring into the flow-through vessel.
4. Align the marking on the sensor with the top edge of the coupling ring.
5. Tighten the coupling ring by hand.
6. Tighten the coupling ring approximately a quarter turn further with the M32 assembly wrench to ensure the sensor is firmly attached.

NOTE: Open the feed slowly during commissioning to prevent damage from shock pressure.

4 Measuring / Operation

4.1 Run-in Period

Polarization: After refilling, immerse the connected and voltage-supplied sensor in a chlorine solution (at least 5 mg/l) for one hour. The sensor can be calibrated after approximately 20 minutes of stabilization, with a post-calibration recommended after one day.

NOTE: The sensor must remain filled with electrolyte and supplied with electrical voltage. If stored, it must be unfilled.

4.2 Check of the Sensor / Analysis

Calibration is performed as a single-point calibration, typically using the DPD method for total chlorine as a reference. Detailed calibration procedures are found in the monitor's operating manual.

4.3 Chlorine Measurement

The sensor measures both free and bonded chlorine. Values determined by the DPD-3 method (total chlorine) are comparable to sensor readings. Interfering factors include chlorine dioxide, ozone, and hydrogen peroxide.

5 Maintenance, Cleaning, Storage

5.1 Cleaning the Measurement Electrode / Exchanging the Membrane Cap and Electrolyte

Disconnect the sensor before maintenance. If calibration is difficult due to low readings, clean the measurement electrode with the polishing strip.

1. Uncover the valve opening by lifting the hose ring.
2. Unscrew the membrane cap and discard the electrolyte solution.
3. Rinse the electrode finger and membrane cap with clean water and dab dry.
4. Clean the measurement electrode by running its tip over the polishing strip 2-3 times. NOTE: Do not polish off the brown coating on the reference electrode, as this will destroy the sensor.
5. Refill the membrane cap with fresh electrolyte, screw it onto the sensor shaft, and repolarize the sensor. If calibration is still not possible, change the membrane cap.

5.2 Cleaning

Removing Lime Deposits:

1. Unscrew the membrane cap and discard the electrolyte solution.
2. Immerse the membrane cap in 10% acetic acid for several hours.
3. Rinse the membrane cap thoroughly with clean water.
4. Refill with fresh electrolyte and reassemble.

5.3 Storage

NOTE: Store the sensor unfilled.

1. Unscrew the membrane cap and discard the electrolyte solution.
2. Rinse and dust-free dry the membrane cap and electrode finger.
3. Loosely screw the dry membrane cap onto the sensor shaft, ensuring the membrane disk does not touch the electrode finger.

For recommissioning, clean the electrode tip with the polishing strip and use a new membrane cap. Lime deposits can be removed from the membrane cap by soaking in 10% acetic acid.

5.4 Maintenance Equipment and Replacement Parts

6 Disposal

Dispose of waste in compliance with local laws and regulations. The WEEE Directive marking on the product indicates it should not be disposed of with general waste. Recycle responsibly to promote sustainable reuse of material resources.

7 Technical Data

7.1 Measurement Characteristics

• Measuring Principle: Membrane-covered, amperometric sensor with potentiostatic three-electrode system and integrated measuring electronics.
• Measuring Range: TCML 412 N: 0.01–2.00 mg/l total chlorine. TCML 412 M12-2: 0.01–2.00 mg/l total chlorine (upper limit depends on slope).
• Response Time (t90): Approx. 120 s.
• pH Dependency: Approx. 10% slope loss per pH unit.
• Temperature Compensation: Internal, automatic via integrated temperature sensor.
• Polarization Time: Approx. 1 hour on commissioning or after electrolyte exchange.
• Calibration: Single-point calibration, e.g., with photometric measurement (DPD method).

7.2 Application Characteristics

• Temperature Range: 0–45 °C (32–113 °F) with automatic temperature compensation.
• pH Application Range: pH 4–12.
• Max. Allowed Overpressure: 3 x 10^5 Pa (3.0 bar) for D-CL and D 19 vessels. Pressureless operation in the flow-through vessel is recommended.
• Working Life of Membrane Cap: Typically 1 year (depending on measuring medium).
• Approach Flow: Recommended minimum flow rate: D-CL >30 l/h, D 19 >15 l/h.
• Typical Application Range: Drinking water, swimming pool water, and mains water in flow-through vessels.

7.3 General Data

• Dimensions: TCML N: 200 mm length, 25 mm diameter.
• Membrane Cap: M48.
• Membrane Type: Microporous, hydrophilic membrane.
• Electrolyte: ELY-TCML 412 N (from ZBK-TCML 412 N).
• Materials: Shaft (PVC), Membrane cap (PVC), Membrane holder/counter electrode (Stainless steel), Working electrode (Gold), Reference electrode (Ag/AgCl), Hose ring (Silicone), Cable gland (Polyamide).

7.4 Electrical Data

• TCML 412 N: 2-wire connection via cable (AK-Cl 298). 12–30 V DC power supply from monitor. Output signal: 4–20 mA.
• TCML 412 M12-2: 5-pin M12 flange connector for ADA Cl/IDS adapter. Power supply: +/- 5–15 V DC via MIQ/IDS module. Nominal slope: -1000 mV/ppm.

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