Point level switch
Feb 07, 2013
Point level switchThe Endress+Hauser Liquiphant FailSafe FTL8x series of point level switches have two relay outputs, a 4–20mA output that connects to a failsafe switching unit with a two-channel output, safety contacts, and a safety locking function. The 4–20mA output can be connected directly to a safety PLC or similar system for minimum and maximum safety applications up to SIL3. The 4–20mA signal jumps from high to low current when the minimum or maximum point level is reached for reliable detection by the safety system. In addition, a permanent live signal of 0.25 Hz is superimposed on the sensor output to indicate the sensor is operating in the “good” state. The level switch meets SIL3 requirements in accordance with IEC 61508, IEC 61511-1, ISA-84-1 and DIN EN ISO 13849. The FTL8x switches meet ATEX, CSA, FM, UL, IEC ex, NEPSI and TIIS requirements for use in non-hazardous areas. Special models are available for use in hazardous areas or applications with high pressures.
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