20.2990 Connecting cable
Connecting cables, plugs and connectors for pH and redox electrodes, electrical conductivity and temperature sensors
Short description
When using electrochemical sensors, special connecting cables and plug connections are used to analyze the parameters of liquids. JUMO offers a selection of different reliable designs. They are either cables together with mounted connectors or cable coils or plugs/connectors for self-mounting.
In most cases, the following rules apply:
The cable length between the electrochemical sensor and the converter/indicator/regulator should be as small as possible. Here we are talking about typical cable lengths from 5 to 10 meters to ensure maximum functional reliability.
If, in exceptional cases, long lengths are required, then the technical documentation for sensors and measuring devices must be taken into account.
The connection between the sensor and the converter must be made without the use of additional terminal connections or extension cords.
Measurement of pH and redox potential
When measuring the pH and redox potential, coaxial cables of a special design are used. When measuring these values, a small potential difference is formed on the sensor and transmitted to the converter. These partially very high-resistance measurements (potentiometric principle, internal resistances up to several gigaohms) are sensitive to electrical interference and radiation. Even the movement of the cable under adverse circumstances can lead to measurement errors. An additional insulating layer of the JUMO coaxial cable increases the insulation resistance of the line and allows a reliable connection of the sensor to the converter. Coaxial cables, which are standard in computers and radio engineering, are not suitable for use and can damage sensors. This can lead to both very rapid sensor failure and a shortened service life. For electrodes with an integrated temperature sensor, there are coaxial cables with an appropriate connector (e.g. Variopin [VP]).
Conductive measurement of electrical conductivity
Connecting cables for conductometric cells (standard sheets 202922-202930) are also optimized for the appropriate application. In this case, a low-amplitude alternating voltage is transmitted in the range from several hertz to several kilohertz. These cables are also shielded. The shielding itself is made in accordance with the required specifications and is optimized for these applications. To increase the reliability of twisted pair signal transmission, the single cores must be twisted.