The EtherCAT terminals in the ELX series have been expanded by the addition of analogue input terminals with TwinSafe SC (single channel) technology. These compact I/O terminals can be used to support applications in the hazardous areas that require both intrinsically safe signal transmission and functional safety capabilities.
These terminals, which are certified compliant with the specifications of the ATEX and IECEx standards, enable direct connection of intrinsically safe field devices through to Zone 0/20 based on an integrated safety barrier. The new terminal designs extended by TwinSafe SC technology also make it possible to achieve safety level equivalent to PL d/Cat. 3 according to EN ISO 13849-1 or SIL 2, according to EN 62061. In this way, it is possible to sue all process data existing in a system for safety technology too, such as to monitor the speed of fans in areas sensitive to explosion hazards.
These I/Os are available as 12mm wide terminals with two or four analogue input channels for 0/4…20mA, and for RTD resistance sensors, thermocouples/mV and strain gauges. Furthermore, a single-channel terminal is available for the direct connection of intrinsically safe incremental encoders, which evaluates a diagnostic-enabled NAMUR signal in accordance with IEC 60947-5-6.
With the aid of TwinSafe technology, it is possible to make use of standard signals for safety-related tasks in any network or fieldbus system. The data from a TwinSafe SC terminal is fed to the TwinSafe Logic, where it undergoes safety-related multi-channel processing. The data originating from different sources is analysed, checked for plausibility and submitted to a voting process. This is done by certified function blocks such as scale, compare/voting (1oo2, 2oo3, 3oo5) and limit. For safety reasons, at least one of the data sources has to be a TwinSafe component.