Main drives "safely-limited speed"
For precise speed control in rolling mills the main drives as well as the roughing stand and coilers need to be equipped with an encoder. In addition, it is often necessary to provide increased protection for personnel during the following operating statuses:
- Safe standstill
- Safly-limited speed
- Maintenance work on a live system
A sensible solution in this case is an overspeed switch that operates independent of the encoder and fulfils the special safety requirements (Safety Integrity Level (SIL) / Performance Level (PL)).
To meet these requirements Johannes Huebner Giessen supplies the overspeed switch, type EGS(H)® 41, which is certified up to SIL 2 to IEC 61508 and PL d to DIN EN ISO 13849. In addition to two safe switching outputs for speed monitoring of over- and underspeeds it offers integrated standstill and slip monitoring functionality as well as a diagnostics switch to monitor safety functions integrated in the device. The programming software included in the scope of supply supports user-friendly parameterization via a USB interface.