Thickness measuring systems for steel strips and sheets
nokra develops and manufactures measuring and inspection systems for use in the steel, aluminum and automotive supply industries. The optical measuring systems are also used in plant engineering and in the processing of vehicle windows. The laser-based systems measure and inspect geometric features such as length, width, thickness, profile, shape and position of e.g. sheet metal, strips, plates and forged test pieces in solid forming and windshields.
The data recorded during the measurement is evaluated and displayed graphically and clearly for the operator. The digital data can also be used to carry out analyses and quality checks on the products and feed them back into the overall production process. This makes it possible to optimize the process sequences.
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“The Deditec modules ensure that nokra systems are reliably operational – even under demanding industrial production conditions. In applications with very long cable runs, the analog current signals are transmitted without interference.”
In the product area of thickness measuring systems for steel strip and sheet metal, the thickness measurement values should not be transmitted digitally but as analog signals, depending on the area of application in production. For this purpose, the digital measurement data is converted into analog values via an interface converter and output. For this interface extension, nokra uses three modules from Deditec. The ready-to-use modules NET-DEV-DIO 1-8, NET-CPU-Base and NET-DEV-DA2_ISO are installed in the control cabinet on a top-hat rail without wiring and can be configured to send either current or voltage signals, depending on the customer’s requirements.
The thickness values sent by the measuring system are sent to the two-channel converter in synchronization with the strip feed. Here, the values are converted and sent to two analog channels: one for the sheet thickness, the other for the thickness deviation. This allows the converted signals to be sent directly to a roll in order to control its roll gap and adapt it to different sheet thicknesses. In this case, the thickness measuring system is not only used to determine and control the sheet thickness, but also as a “trigger” to control other machines.
