Overview

The CP4.0 is a chlorine indicator sensor designed to measure total chlorine (free + bound chlorine) with reduced dependence on pH. It is suitable for applications including swimming pool water, drinking water, seawater, and brine (up to 15% NaCl). The sensor tolerates some surfactants and works with various inorganic chlorine compounds such as sodium hypochlorite, calcium hypochlorite, chlorine gas, and electrolytically generated chlorine.

Measuring System and Electronics

• Membrane-covered amperometric potentiostatic 3-electrode system with integrated electronics.
• Available in analog, digital, and mA output versions:
• Analog: voltage output, not galvanically isolated, analog internal processing.
• Digital: fully galvanically isolated, digital internal processing, output can be analog or digital.
• mA version: current output, not galvanically isolated.

Performance Specifications

• Measuring range varies by model, with sensor slope variability between 65% and 150% of nominal slope affecting effective range.
• Accuracy after calibration at 25°C, pH 7.2:
• 2 mg/L range: <2% error at 0.4 and 1.6 mg/L.
• 20 mg/L range: <1% error at 4 mg/L, <3% at 16 mg/L.
• Slope drift approximately -1% per month under repeatability conditions.
• Working temperature: 0 to +45°C for measuring water; ambient 0 to +55°C.
• Automatic temperature compensation via integrated sensor; avoid sudden temperature changes.
• Maximum working pressure:
• Without retaining ring: 0.5 bar, no pressure impulses or vibrations.
• With retaining ring (option 2) in TARAflow FLC: up to 3 bar, no pressure impulses or vibrations.

Operational Parameters

• Flow rate: approx. 15-30 L/h (15-30 cm/s) with minimal flow dependence.
• pH range: 4 to 12 with reduced pH dependence.
• Conductivity range: 10 µS/cm to 200 mS/cm (including brine).
• Run-in time: approx. 2 hours at first start-up.
• Response time (T90): approx. 3 minutes (5 minutes in brine).
• No zero point adjustment required.
• Calibration performed on device using DPD-4 method (DPD-1 + DPD-3).

Interferences and Limitations

• Cross sensitivities: chlorine dioxide (ClO2) factor 1, ozone (O3) factor 1.3.
• Corrosion inhibitors and water hardness stabilizers may cause measurement errors.
• Disinfectant absence should not exceed 24 hours.

Physical and Connection Details

• Connections:
• mV and Modbus versions: 5-pole M12 plug-on flange.
• 4-20 mA version: 2-pole terminal or 5-pole M12 plug-on flange.
• Maximum sensor cable length:
• Analog: less than 30 m.
• Digital: greater than 30 m permissible.
• Protection rating: IP68 for 5-pole M12 flange, IP65 for 2-pole terminal with mA hood.
• Materials: microporous hydrophilic membrane, PVC-U, PEEK, stainless steel 1.4571.
• Dimensions: approx. 25 mm diameter; length varies by version (190-220 mm).

Storage and Maintenance

• Transport temperature: +5 to +50°C (sensor, electrolyte, membrane cap).
• Storage:
• Sensor dry and without electrolyte: no limit at +5 to +40°C.
• Electrolyte in original bottle: protected from sunlight at +5 to +35°C, minimum 1 year shelf life.
• Membrane cap in original packaging: no limit at +5 to +40°C; used caps cannot be stored.
• Maintenance:
• Check measuring signal at least weekly.
• Replace membrane cap and electrolyte annually, depending on water quality.

Options and Spare Parts

• Option 1: Membrane cap M48.4S for seawater or brine applications.
• Option 2: Retaining ring for operation above 0.5 bar pressure in TARAflow FLC; dimensions 29 x 23.4 x 2.5 mm, slitted PETP with selectable groove positions.
• Spare parts include membrane caps (M48.4E standard, M48.4S for brine), electrolytes (ECP1.4/GEL, ECP2S/GEL), Emery O-ring (S1), and NBR O-ring.

Technical Data by Version

1. Analog Output, Analog Internal Processing

• Measuring ranges: 0.005–2.000 ppm (high sensitivity), 0.05–20.00 ppm (normal range).
• Output: voltage 0 to ±2000 mV depending on model.
• Output resistance: 1 kΩ.
• Power supply: ±5 to ±15 VDC or 10–30 VDC depending on model.
• Galvanic isolation required.
• Connection: 5-pole M12 plug-on flange.

2. Analog Output, Digital Internal Processing

• Measuring ranges similar to analog version.
• Output: analog voltage 0 to ±2 V (max ±2.5 V).
• Power supply: 9–30 VDC, current approx. 7–30 mA.
• No galvanic isolation required.
• Connection: 5-pole M12 plug-on flange.

3. Digital Output, Digital Internal Processing

• Measuring ranges: 0.005–2.000 ppm and 0.05–20.00 ppm.
• Output: Modbus RTU over RS485.
• Power supply: 9–30 VDC, current approx. 7–30 mA.
• No galvanic isolation required.
• Connection: 5-pole M12 plug-on flange.

4. 4-20 mA Output, Analog Internal Processing

• Measuring ranges: 0.005–0.5 ppm up to 0.05–20 ppm.
• Output: 4–20 mA current loop, uncalibrated.
• Output resistance: 32 Ω at lowest range, down to 0.8 Ω at highest range.
• Power supply: 12–30 VDC.
• Galvanic isolation required.
• Connections:
• 2-pole terminal clamp (recommended cable: round, 4 mm diameter, 2 x 0.34 mm²).
• 5-pole M12 plug-on flange with defined pin functions.

Compliance and Certifications

• EMC tested.
• RoHS compliant.

Critical Notes and Best Practices

• Ensure no pressure impulses or vibrations during operation, especially above 0.5 bar.
• Avoid sudden temperature changes to maintain measurement accuracy.
• Regular maintenance and calibration are essential for reliable operation.
• Use appropriate membrane caps and electrolytes based on application (freshwater vs. seawater/brine).
• Observe cable length limits depending on analog or digital signal processing to avoid signal degradation.