Eddy current system measures strip vibration in hot-dip coating systems

In hot-dip coating plants, steel strips are coated with molten zinc, zinc alloys and aluminium alloys in a continuous process. Inductive eddy current sensors are used in electromagnetic systems for strip stabilisation. Due to the high speed of the belts, vibrations occur. To minimise this, electromagnetic stabilisation systems from market leader EMG are used, in which 10 to 16 EU40 inductive sensors from Micro-Epsilon are installed.

During the coating process, the inductive sensors measure the vibrations as distance values on a non-contact basis. These are transmitted to the electromagnetic stabilisation system, which enables continuous monitoring of the entire system, thus ensuring reliable vibration reduction. The EU40 inductive sensors are extremely robust and can easily withstand the high temperatures, as well as the chemical and mechanical loads of the system. They work with a large measuring range of 40mm and are operated using the compact eddyNCDT 3020 industrial controller in a version (DT3029/EMG) specially adapted for the EMG application. The controller is also extremely robust and is designed with a high degree of protection (IP67). Due to its compact design and high temperature resistance (up to 105 °C), it can be integrated directly into the EMG stabilisation unit.

A high EMC immunity ensures that the sensor-controller unit delivers stable measurement results even in the vicinity of electromagnets. Due to the short cable length of 1 m and the excellent temperature stability of the system, the precision and stability of the output signal increases enormously. This is transmitted to the control unit up to 50 m away via the analogue current output.

Robust system for demanding environments

The eddyNCDT 3020 measurement system delivers precise and stable measurements even under extreme conditions – up to a maximum ambient temperature of 200°C (controller up to 105°C, sensor up to 200°C). The DT3020 controller offers high resolution and detects fast movements due to a high measurement rate of 80kSa/s. The cut-off frequency of 5kHz (-3dB) reduces unwanted noise and ensures stable measurements with high precision (resolution up to 40nm). The system is factory-tuned to ferromagnetic or non-ferromagnetic target materials. Its robust, IP67-protected design, compactness (102 x 53 x 30mm) and flexible connection and configuration options make it suited to industrial environments and machine integration.