Connection cable for pH/redox Length: 3 metres Cable type: pH and redox connection cable Ø 5 mm, 75 °C Connection end 1 (sensor side): rotatable cable socket Connection end 2 (device side): without Electronic sensors for analysing liquids require special connection cables and plug connectors. The following applies in principle: The connection between an electrochemical sensor and the transmitter/indicator/controller should be as short as possible. Normally, the cable length is 5 to 10 metres to ensure a high level of functional reliability. If longer cable lengths are required in exceptional cases, the technical documentation for the sensors and measuring devices should be consulted. The cable between the sensor and the analyser must be laid directly, without interruptions such as terminal strips or cable extensions. pH and redox measurement Special coaxial cables with a special design are used for pH and redox measurement. During these measurements, the sensor generates low-intensity DC voltages which are transmitted to the analyser. Due to the sometimes very high internal resistance (potentiostatic measuring principle with internal resistances of up to several gigaohms), these measurements are extremely sensitive to electrical interference and the effects of radiation. Under unfavourable conditions, even minimal movements of the cable can lead to measurement value distortions. An additional insulation layer of the JUMO coaxial cable increases the insulation resistance, which enables a secure connection of the sensor to the transmitter. Conventional coaxial cables from the antenna and computer sector are not suitable for this application and can damage the sensors. This can lead to immediate failure of the sensor as well as a shortened service life. For multiple sensors, for example with integrated temperature sensors, coaxial cables with single wires are available, such as the Variopin (VP).

Flow monitors for disinfection variables Membrane-covered sensors for water disinfection (e.g. free chlorine or total chlorine, ozone, chlorine dioxide, etc.) must be operated with a minimum flow rate of 15 cm/s. The flow monitor is integrated into the sample water supply line, in series with the disinfection sensor, and monitors the required minimum flow to the sensor. Below the minimum flow velocity, the sensors measure values that are too low. This can cause a connected control system to dangerously overdose or underdose. Above the minimum incident flow velocity, the measuring signal is only slightly influenced by the incident flow velocity. The flow monitor consists of a flow body, a needle valve insert for flow regulation and an inductive proximity switch, which is controlled by a float in the medium flow. When the minimum flow velocity is reached or exceeded, the float rises and the contact of the inductive proximity switch switches. The contact can be used, for example, to control a binary input of the controller for standard signals, JUMO AQUIS 500 AS. If the flow is too low, the controller is set to the ‘HOLD’ state. This prevents incorrect dosing.   Areas of application Flow monitoring when using sensors for free chlorine, chlorine dioxide, ozone, hydrogen peroxide or peracetic acid