Apparatus For Fault Tolerant Digital Inputs

An input termination board for use with an industrial controller in a safety system is disclosed herein. The industrial controller may be populated with standard input modules according to the application. The termination board, in conjunction with the controller allows the standard input modules to be used as safety inputs. The termination board provides simplified wiring between the input modules and the remote devices by splitting each of the signals generated by the remote device into separate inputs for two different input modules. In addition, a program executing on the controller of the safety system monitors and tests each of the inputs in both input modules to verify proper operation of the inputs. If the program detects a fault in either input module, the safety system may alternately shut down according to a fail-safe procedure or continue operating under a fault-tolerant mode of operation.