Conductivity transmitter

1 Overview

The conductivity transmitter is a process meter (integrated transmitter) that measures the ion concentration indirectly by measuring the conductance value of a solution, and can continuously detect the conductivity of an aqueous solution in an industrial process on-line.

Because the electrolyte solution is the same good electrical conductor as the metal conductor, there must be an electrical resistance when the current flows through the electrolyte solution, and it is in accordance with Ohm's law. However, the resistance temperature characteristics of liquids are contrary to those of metal conductors and have negative temperature characteristics. In order to distinguish from the metal conductor, the conductivity of the electrolyte solution is represented by conductance (reciprocal of resistance) or conductivity (reciprocal of resistivity). When two electrodes that are insulated from each other form a conductivity cell, a current loop is formed if the solution to be measured is placed in between, and a constant voltage alternating current is passed through. If the voltage size and the electrode size are fixed, the loop current and the conductivity have a certain function. In this way, measuring the current flowing in the solution to be measured, the conductivity of the solution to be measured can be measured.

2 circuit principle

The conductivity transmitter is mainly composed of a conductivity cell, an electronic module, a display head, and a housing. The conductivity cell is alternated by a square wave in the electronic unit. A constant voltage alternating current with a frequency of about 800-1000Hz is used. The power supply has good voltage regulation characteristics. Under no-load conditions of the transmitter, the DC24V power supply is 16-38V and AC220V. The power supply varies from 170 to 250V and does not affect the transmitter output by more than 0.5% (full scale).

3 Technical parameters

Power supply: 24VDC

Measuring range: 0.05 to 200 μS/cm

Measured variables: conductivity, resistance, temperature, concentration

Output signal: 4-20mA

Permissible medium pressure: standard ≤ 700Kpa (more than 700Kpa, user specified)

Temperature compensation method: automatic compensation

Concentration:0~9999(%,ppm,mg/L,TDS)

Enclosure protection level: Panel mounted IP54 (panel), IP30 (shell), field instrument IP65

Power supply: 100/115/230VAC+10/+15%, 48-62Hz24VAC/DC+20/-15%

Communication: HART, PROFIBUS-PA, DP

Medium temperature: ABS material -10-60 °C stainless steel material -20-110 °C

Electrode: titanium electrode constant 0.01 and 0.1

Accuracy: 1%

Load characteristics: 0-500 ohms

Installation method: flange, thread, pool

4 main features

Integration of integrated structure, both on-site display and remote transmission, novel structure, lightweight and flexible, reliable performance;

4-20mA standard signal output realizes two-wire transmission, which can be conveniently composed of measuring instruments and measuring instruments;

A variety of installation structure, convenient and flexible installation, can meet the different needs of users;

The product has good load performance and strong anti-interference ability. It can meet the different needs of users with two different electrodes. The transmission distance is long and can reach 1500 meters.

Reverse polarity protection, surge voltage protection and overload protection;

Medium temperature: 0-100 °C, pressure: ≤ 1.0Mpa, measuring range: 0-10000μs/cm;

Secondary reverse osmosis combined with pre-conductivity and post-resistance between EDI and ion exchange resin mixed bed;

Four range, automatic switching, automatic carry display, simple operation, high measurement accuracy;

Automatic temperature measurement, automatic solution temperature compensation;

Using 31/2 digit liquid crystal digital display, temperature and measured value display at the same time, beautiful appearance, clear display; with conductivity, resistivity over limit alarm output, control function, conductivity (0 ~ 1999μS · cm-1), resistivity (0 to 18.25 MΩ·cm);

Set the relay operating point within the measuring range;

Can be operated as meter output or transmitter.

5 application areas

The basic model sends it to provide simple measurement and alarm functions.

Extended Functions Software and hardware can be modularized and can be applied to special occasions. If needed, expansion modules can be used.

Application of ultra-pure water, water treatment, ion exchange, sewage, reverse osmosis, cooling water desalination.

Suitable for two-electrode measuring sensors (conducting or inductive). Electric shock can be set to USP alarm (pre-alarm/adjustable). Electric shock can be delayed for a long time.

Suitable for cooling water applications Specialized ultrapure water compensation Polarization monitoring and alarm signal output Direct access to manual contact control HART or PROFIBUS-PA communication expandable base unit.