3/29/2016 3:46 PM | |
Joined: 9/27/2006 Last visit: 9/22/2024 Posts: 12282 Rating: (2685)
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Hello Niranjankrmr; Let's presume you understand the steps to upgrade the CPU system from a regular S7-400 to a redundant H-system. The next step is to consider how the I/O rack(s) you have presently can be used in the S7-400H system. By the way, the best source of information on the S7-400H I/O configuration would be this manual, which you should study and consult whenever you have this sort of question: SIMATIC Fault-tolerant systems S7-400H https://support.industry.siemens.com/cs/ww/en/view/82478488 There are 4 ways you can connect the I/O racks on a S7-400H system, in your situation you can use the "single-channel one-sided" configuration (see the attachment below, from the same naual). This means that the I/O rack can be attached to only one of the redundant CPUs. While both CPUs are working in redundancy (master , on rack 0, and reserve on rack 1). If the rack number of your I/O is even, you will be attached to the rack 0 (master) CPU; if the number of the I/O rack is odd, it will be attached to the rack 1 (reserve) CPU. While the redundancy is working well, the I/Os will be read by the attaching CPU and the values will be transferred to the other CPU as a matter of course, so both CPUs will have the present values of the I/O. But if you lose the redundant functions and go to stand-alone mode for any reason, you will lose all I/Os that were attached to the master CPU until redundancy is achieved once more. Study chapter 13 of the manual to see what other options you can achieve with your I/O rack, and see the advantages and cost that would entail. Hope this helps, Daniel Chartier |
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