Introduction

4-channel input terminal, thermocouple with wire break detection, TwinSAFE Single Channel

The EL3314-0092 analog input terminal is based on the EL3314-0002, but is also equipped with the TwinSAFE SC function.

The EL3314-0092 analog input terminal allows four thermocouples to be connected directly. The channels are electrically isolated from each other and from the E-bus, thus preventing adverse effects and damage due to cross currents. Various types of thermocouple are supported; the conversion of the voltage to temperature is already carried out within the terminal. Wire break is signaled by error LEDs and on the fieldbus. The cold junction compensation is carried out by an internal precise temperature measurement at the connection terminals; however, operation with an external cold junction or voltage measurement without cold junction calculation is also possible.

The TwinSAFE SC technology (TwinSAFE Single Channel) enables the use of standard signals for safety tasks in any networks or fieldbuses. The standard functionalities and features of the I/Os are retained. The data of the TwinSAFE SC I/Os are routed to the TwinSAFE logic and processed there in a multichannel safety-related manner. In the Safety Logic the data originating from different sources are analyzed, checked for plausibility and submitted to a ‘voting’. This is done using certified function blocks such as Scale, Compare/Voting (1oo2, 2oo3, 3oo5), Limit, etc. For safety reasons, at least one of the data sources must be a TwinSAFE SC component. The remainder of the data can originate from other standard bus terminals, drive controllers or measuring transducers.

With the aid of the TwinSAFE SC technology it is typically possible to achieve a safety level equivalent to PL d/Cat. 3 in accordance with EN ISO 13849-1 or SIL 2 in accordance with EN 62061.