Mixed double

摘要

Position feedback signals, such as the open-closed signals from butterfly and ball valves or the valve position of three-way flaps, are extremely common in process engineering. The sensors required forthis are generally installed in a plastic housing with a somewhat complex mechanical design. The huge diversity of the individual components puts up the price and usually means costly readjustment work in order to set the switch points. The Atex directive also stipulates that all the different components, such as the housing, sensors and microswitches including their associated wiring, must be tested separately. Testing in compliance with the SIL Directive IEC 61508 further increases the testing effort and the expense involved.