Introduction

The BMXSDI1602 safety input module presents the following features:

  • 16 Type 3 (IEC61131-2) inputs, in two electrically non-isolated groups of 8 inputs.

  • 24 Vdc rated input voltage.

  • Achieves the following:

    • SIL3 IEC61508, SILCL3 IEC62061.

    • SIL4 EN5012x.

    • Category 2 (Cat2) / Performance Level d (PLd) ISO13849 using 1 input channel (one-out-of-one (1oo1D) evaluation).

    • Category 4 (Cat4) / Performance Level e (PLe) ISO13849 using 2 input channels (one-out-of-two (1oo2D) evaluation).

  • Compatible with 2 or 3 wire proximity sensors.

  • Provides optionally two 24 Vdc outputs (VS1 and VS2) for short-circuit to 24 Vdc supervision:

    • VS1 to monitor short-circuit on inputs 0...3 (rank A & B).

    • VS2 to monitor short-circuit on inputs 4...7 (rank A & B).

  • Monitor external 24 Vdc sensor supply voltage.

  • LED diagnostic display provided for the module and for each input channel.

  • Configurable (enable/disable) channel wiring diagnostics that can detect the following conditions:

    • Open (or cut) wire.

    • Short circuit to the 0 V ground.

    • Short circuit to the 24 Vdc (if sensor power is internally provided).

    • Crossed circuits between two channels (if sensor power is internally provided).

  • Module hot swap during runtime.

  • Module CCOTF when operating in maintenance mode. (CCOTF is not supported in safety mode.)

High Availability

You can use two sensors connected two different input channels located on different input modules to monitor the same physical value, and thereby increase system availability.

The following figure illustrates the redundant digital input configurations:

The input state value from sensor 1 and sensor 2 are sent by input module 1 and input module 2, respectively, over a black channel to a safety CPU. The CPU executes a dedicated function block, S_DIHA, to manage and select the data from the two input modules. This function block operates as follows:

  • If the health status of the input data coming from module 1 is OK, the input data from this module is used in the safety function.

  • If the health status of the input data coming from module 1 is not OK, but the health status of the input data coming from module 2 is OK, the input data from module 2 is used.

  • If the health status of the input data from both module 1 and module 2 is not OK, then the state of the input is set to the safe state (“0”) in order to activate the safety function.

Refer to the description of input application wiring examples for details on how to wire the module for high availability.