Eddy Current Measurement System for Strip Vibration in Hot-Dip Coating Plants
Steel strips are coated with molten zinc, zinc alloys, and aluminium alloys in a continuous process in hot-dip coating plants. During this process, inductive eddy current sensors are used in electromagnetic systems for strip stabilisation, but at high belt speeds, vibrations occur. To reduce this, electromagnetic stabilisation systems from EMG can be used, which include 10 to 16 EU40 inductive sensors from Micro-Epsilon
During the coating process, the inductive sensors measure vibrations as distance values in a non-contact manner. These are then transmitted to the electromagnetic stabilisation system, which enables continuous monitoring of the entire system to ensure reliable vibration reduction.
The EU40 inductive sensors are robust and can withstand high temperatures and the chemical and mechanical loads of the system. They feature a measuring range of 40mm and are operated by the eddyNCDT 3020 industrial controller in a version specifically adapted for the EMG application. The controller has been designed with a high degree of protection; its compact design and high temperature resistance of up to 105°C enable it to be integrated directly into the EMG stabilisation unit.
A high EMC immunity ensures the sensor-controller unit provides stable measurement results, even in the presence of electromagnets. Due to the short cable length and the system's enhanced temperature stability, the precision and stability of the output signal have increased. This is transmitted to the control unit up to 50m away via the analogue current output.
The eddyNCDT 3020 measurement system can provide accurate, stable measurements under extreme conditions, with a maximum ambient temperature of 200°C for the sensor and 105°C for the controller. The DT3020 controller offers high resolution and can detect fast movements thanks to its 80kSa/s measurement rate. The 5kHz cut-off frequency reduces unwanted noise and ensures stable measurements with a resolution of up to 40nm. The system is factory-tuned to ferromagnetic or non-ferromagnetic target materials. Its IP67-protected design, compactness, and flexible connection and configuration options make it suitable for industrial environments and machine integration.