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| 1/12/2008 12:15 PM | |
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Posts: 121 Rating:
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It's getting back the values saved on the EPROM. So before pulling the MCC you should do a save on memory card. Then it stores the actual DB values |
| 1/12/2008 4:52 PM | |
Joined: 1/7/2006 Last visit: 11/17/2023 Posts: 2705 Rating:
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Hi Peter, There is a newer Firmware Version: Operating System Updates for CPU 315F-2 DP Retentivity of load memory, system memory and RAM Your CPU is equipped with a service-free retentive memory, i.e., its operation does not require a buffer battery. Data is kept in retentive memory across POWER OFF and restart (warm start).
Your program in load memory is always retentive: It is stored on the SIMATIC Micro Memory Card, where it is protected against power failure or CPU memory restart.
In your configuration (Properties of CPU, Retentivity tab), specify which part of memory bits, timers and counters should be kept retentive and which of them are to be initialized with "0" on restart (warm restart). The diagnostics buffer, MPI address (and transmission rate) and operating hour counter data are generally written to the retentive memory area on the CPU. Retentivity of the MPI address and baud rate ensures that your CPU can continue to communicate, even after a power loss, memory reset or loss of communication parameters (e.g. due to removal of the SIMATIC Micro Memory Card or deletion of communication parameters). Retentive data in work memory Therefore, the contents of retentive DBs are always retentive at restart and POWER ON/OFF. Retentive data blocks can be uploaded to the work memory in accordance with the maximum limit allowed by the work memory. In the case of CPU versions V2.0.12 and higher, non-retentive DBs are also supported. Nonretentive DBs are initialized from the load memory with their initial values whenever a restart is performed or when the power is switched off and then on again. Non-retentive data blocks and code blocks can be loaded in accordance with the maximum work memory limit. CPUs Length of the non-volatile work memory for retentive data blocks CPU 312 32 KB CPU 313, 314 64 KB CPU 315 128 KB CPU 317 256 KB CPU 319 700 KBPromming (RAM to ROM) When writing the RAM content to ROM, the actual values of the DBs are transferred from RAM to load memory to form the start values for the DBs.
This function is only permitted when the CPU is in STOP mode. Load memory is cleared if the function could not be completed due to power loss. |
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I hope that the answer will help, if you have still questions, don't hesitate to ask me. |
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