Safety Considerations Guide, Tricon v9.0 - Tuv-fs.com

Guidelines for Tricon Controllers 25Disabled Output Voter DiagnosticA safety application may not disable the output voter diagnostic.Download All at Completion of ProjectWhen development and testing of a safety application is completed, use theDownload All command on the Control Panel to completely re-load the applicationto the controller.Modbus Master FunctionsModbus Master functions are designed for use with non-critical I/O points only.These functions should not be used for safety-critical I/O points or for transferringsafety-critical data using the MBREAD and MBWRITE functions.Peer-to-Peer CommunicationPeer-to-Peer communication enables Triconex controllers (also referred to asnodes) to send and receive information. If a node sends critical data to another nodethat makes safety-related decisions, you must ensure that the application on thereceiving node can determine whether it has received new data.If new data is not received within the time-out period (equal to half of theprocessing-tolerance time), the application on the receiving node should be able todetermine the action to take. The actions may include one or more of the following:• Use the last data received for safety-related decisions in the application.• Use default values for safety-related decisions in the application.• Monitor the status of the TR_URCV and TR_PORT_STATUS functions todetermine whether there is a network problem that requires operatorintervention.The specific actions that an application should take depends on the unique safetyrequirements of your particular process. The sections that follow summarize themain types of actions entailed in the use of Peer-to-Peer send and receive functions.Sending NodeThe actions required in the logic of the sending application are:Chapter 2Application Guidelines