5/25/2016 9:07 PM | |
Posts: 22 Rating: (1) |
please give me a quick short main different between standard and fail-safe module. |
5/25/2016 11:18 PM | |
Joined: 9/27/2006 Last visit: 10/17/2024 Posts: 12289 Rating: (2687)
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Hello William; There are many differences in the components of a F-system compared to a standard CPU + I/O modules, although all are not immediately apparent to the user. For example, test circuits are integrated in all F-I/O modules so the F-CPU can transparently determine the accuracy of all input and outputs required for the safety program. One of the most obvious differences between a standard program and a Safety program, for someone starting to program them, is the requirement for setting monitoring times for different portions of the program: monitoring the cycle time of the Safety program execution, monitoring the communication time between F-CPU and .F-I/O, monitoring the time of communications between F-CPUs, and evaluation the F-system response time. These are all parameters that must be calculated (by the system program and with the help of special documents developed by the Siemens SET team) and integrated in the safety functions. Any exceeding of any monitoring time will cause a shutdown to a safe state of the whole system, even though the reported status of the F-I/O (by themselves) do not cause a shutdown. So, not only does a safety digital input (for example) report on the status of its input signals, it also reports on its operational status to the F-CPU within a predetermined time to ensure the system that it is responsive. Failure to do so disrupts the safety program and causes passivation of the F-DI module. The following manual discusses F-System engineering without getting into the details of each F-CPU family, so it can give general ideas on safety systems. Look in Appedix A for a description of monitoring times. SIMATIC Industrial Software Safety Engineering in SIMATIC S7 https://support.industry.siemens.com/cs/ww/en/view/12490443 Hope this helps, Daniel Chartier |
Last edited by: dchartier at: 5/25/2016 11:21:04 PM |
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