1/10/2020 9:29 PM | |
Joined: 9/27/2006 Last visit: 9/10/2024 Posts: 12282 Rating:
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Hello Rahig8; Please tell us if there is a memory card slotted in the CPU, and if so is it a RAM card? There are 2 types if memory card you can use with a S7-400 for Load Memory, RAMand Flash EPROM. A Flash card will retain the program without battery support, but a RAM card requires that at least one functionning battery be installed in the power supply module. If the battery is missing or weak, you will lose your program when the CPU is de-energised. If this is the case, you would have the symptoms that you describe; but you could download the program to the CPU to return it to normal. Have a look at the following document for more details: How can I get an overview of the S7-400 memory concept? https://support.industry.siemens.com/cs/us/en/view/7302549 Hope this helps, Daniel Chartier |
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