A safety network system is constructed by connecting a safety PLC to a safety slave through a safety network. The safety slave obtains safety input informations from a plurality of safety devices connected thereto and transmits information based on the plurality of safety input informations in response to a request from the safety PLC. At this time, the safety slave determines whether or not a safety condition is satisfied based on the plurality of safety input informations, includes two notification modes, that is, a result notification mode in which a result of determination of safety determined by the above determination is transmitted and a detailed information mode in which the plurality of safety input informations are transmitted as they are as aggregated data, and returns a safety response in any of the modes according to a command from the safety PLC. In the result notification mode, the response can be returned at a high speed because an amount of data is small, and, in the detailed information mode, detailed information can be secured.
A safety condition setting support device is used for a safety network to which an input device and an output device are connected and the output device serves to stop a controlled apparatus based on a detection signal outputted from the input device when the input device has detected a danger condition. The support device serves to set safety conditions for stopping the controlled apparatus within a specified time period and includes an apparatus data memory for storing data related to internal processing times of safety devices connected to the safety network including the input and output devices, data obtaining device obtaining connection data showing connection relationship among the safety devices and transmission intervals among the safety devices or a safety distance between the input device and the controlled apparatus, and a calculating device for obtaining the safety conditions based on these obtained data.
This invention provides an input device of safety unit which enables an error diagnosis result referred to in a process of input processing for generating a control data from raw input signal to be referred by a side using the control data also in a safety unit such as a safety master and safety slave. An input device contains a function of outputting status data indicating the error diagnosis result referred to when input signal is converted to control data and the control data obtained by the conversion in pair, so that when the logical value of the control data is "LOW", whether it originates from that the raw logical value is "LOW" or that "LOW" is compulsorily set due to an error in the terminal can be determined from the logical value of the status data.
Mechanisms and techniques provide a data acquisition basic input output system between a central controller and a set of modules networked to the central controller. The central controller obtains at least one command to be sent to at least one module of the set of modules networked to the central controller and composing a request message containing the command. The request message has an associated timing pattern selected from a plurality of available timing patterns, such as a fixed timing pattern or a variable timing pattern. The central controller transmits the request message to the module(s) according to the associated timing pattern and receives, according to the associated timing pattern, a response message from the module(s). The data acquisition basic input output system communications do not require reliance on transport layer protocols or collision avoidance techniques.
A method and apparatus for the transmission of safe process information including detecting two or more process signals redundantly, identifying an event that is relevant to system safety, and converting said process signals to a single process signal for further system-based processing.
