Switching small loads safely

Both components are used when it comes to switching loads and/or inputs that are sensitive to output test pulses from safety-critical outputs.

In these applications, where safety-critical outputs are actuated by smaller valves or where sensitive inputs are controlled by drive controls, these loads may switch off inadvertently, triggered by the output test pulses. This switching behavior limits availability of the affected systems and generally occurs in all similar safety products.

 

One possibility to avoid accidental switch-offs is to use one of the two filter modules SP-FILTER, which is put between the Q outputs of the I/O modules SP-SDIO84-P1 (with output test pulses) and the respective load. The filter modules suppress the short test pulses so that these can no longer interfere with the connected load.

 

The new SP-SDIO84-P2 I/O module is the first module available in the samos® PRO system where test pulses at outputs Q1 to Q4 no longer occur. The optional filter modules are not required by this module. With one-channel use of the outputs, using the I/O module can achieve a maximum of PL d / category 3 or SILCL 2, with two-channel use a maximum of PL e / category 4 or SILCL 3.

 

All devices from Wieland Electric’s samos® PRO product family have been certified by the German technical inspection authority (TÜV) and can be used in safety-oriented applications up to PL e / Category 4 according to EN ISO 13849-1 or SILCL 3 according to EN 62061.