6/11/2010 6:41 PM | |
Joined: 9/27/2006 Last visit: 10/17/2024 Posts: 12289 Rating: (2687) |
Hello deepak; For redundancy purposes, Siemens proposes 2 levels: - the S7-400H series of controllers, which present hardware redundancy, in a hot-standby configuration. Two exactly similar S7-400H CPUs run the same program; only one is active at a time.; the other remains in active standbyAt the end of every cycle, a very fast link (fiber-optic based) refreshes the memory of the standby CPU, so that at the beginning of all cycles both CPUs have the same contents in memory: code, data, I/O mappings, etc..I/Os are shared over a redundant Profibus-DP link. If the main CPU goes down with any reason, a special interrupt is generated andthe standby CPU picks up the program immediately (with microsecond delay)and continues the process control as if nothing has happened. - For S7-300 and non-redundant CPUs of the S7-400 family, you can use the Software redundancy package This is a warm-standby configuration, slower and less efficient than the H-CPUs. The link between the CPUs is a standard communication link (Profibus, MPI or Ethernet), and it is much slower than the fiber-optic transmissions of the H-CPUs. You have to program implicitely all data exchanges between the main and standby processors, and not all data is transfered, as this would slow down the exchanges even more. Only the redundancy-related data is written to the standby CPU. You do not have to use exactly similar CPUs for Software Redundancy, you could use a S7-300 and a S7-400 pair if you wanted to. You can evenhave different programs in each CPU. as long as the redundancy functions are configured properly; you then accept of course that in case of change-over, the standby CPU might not be able to process all information as the main one did. If your process is not critical (where micro-second shutdowns are intolerable) and you are willing to wait a few cycles between the loss of a main CPU and the activation of a standy CPU, then Software Redundancy can be a solution (much cheaper also; but you get what you pay for...). You already have recieved links to look at the S7-400H family. Here is one to the Software Redundancy manual: http://support.automation.siemens.com/WW/view/en/1137637 Hope this helps, Daniel Chartier |
Last edited by: dchartier at: 6/11/2010 6:45 PM |
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This contribution was helpful to2 thankful Users |
6/12/2010 9:20 AM | |
Joined: 4/5/2006 Last visit: 10/10/2024 Posts: 917 Rating: (63) |
Hi deepak.samal, In PCS7 catalog there are basic info about you are looking for: https://www.automation.siemens.com/infocenter/order_form.aspx?nodeKey=key_518693&lang=en in left pane select Automation and Drives -> Automaton Tecnology -> Automation and control system -> Process control system -> SIMATIC PCS7 look for "SIMATIC PCS 7 Standardcatalog ST PCS 7 for V7" chapter 6 : AS system (power supply, CPU, network card, perifery) chapter 7 : network comunication topologi and component hope can help regards |
6/12/2010 8:36 PM | |
Joined: 9/27/2006 Last visit: 10/17/2024 Posts: 12289 Rating: (2687) |
Hello deepak; You also have access to an excellent ressource in the following S7-400 H manual: http://support.automation.siemens.com/WW/view/en/1186523 It explains in detail the different redundant levels available for the s7-400H system, and there is a complete appendix on redundant I/O wiring. Hope this helps, Daniel Chartier |
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