PLC Brands

For example, there are many applications where the Programmable Logic Controller (PLC®) has been used to control equipment, including the safety-related parts of the control system. Typically, standard PLC controllers used in safety applications are configured in pairs. The redundant controller is used to support a safe and orderly shutdown in the event the primary controller fails. In addition to multiple controllers, safety applications designed using standard PLCs utilize additional I/O inputs to monitor safety system output signals, and more outputs to generate test pulses for the safety system’s input modules. Also, applications designed around standard PLCs require custom software to monitor, control and diagnose the safety system. To summarize, designing safety systems around standard controllers requires additional engineering time, I/O hardware, and wiring to support the safety portion of the application, in addition to the hardware and software required to run the application...