Intrinsically safe signal transmission

The high­ly com­pact ELX series ter­mi­nals, which are cer­ti­fied in com­pli­ance 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 now also make it pos­si­ble to achieve a 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 use 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, for example.

The new I/Os are avail­able as 12 mm wide ter­mi­nals with two or four ana­log input chan­nels for 0/4…20 mA, 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.
Twin­Safe SC technology
With the aid of Twin­Safe SC 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, Lim­it, etc. For safe­ty rea­sons, how­ev­er, at least one of the data sources must be a Twin­Safe SC component.