6/24/2009 6:46 AM | |
Joined: 9/27/2006 Last visit: 9/22/2024 Posts: 12282 Rating: (2684)
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Hello Raymond; Normally you do not download the blocks to the standby CPU. This is done first when the standby CPU requests Link-Up (when it is powered on once the masterCPU is in Run mode, then every scan over the fiber optic connections between the 2 CPUs. Here is a description of the normal procedure from the S7-400H Fault-Tolerant Systems manual: http://support.automation.siemens.com/WW/view/en/1186523 Explanations relating to figure 5-2 System and Operating Modes of the Fault-Tolerant System Item Description 1. Once the power supply has been turned on, the two CPUs (CPU 0 and CPU 1) are in the STOP mode. 2. CPU 0 goes to STARTUP mode and processes OB 100 or OB 102, depending on the type of startup.(Refer to Section 5.3.2) 3. If startup has been successful, the master CPU (CPU 0) changes to single mode (the master CPU processes the user program on its own). 4. If the standby CPU (CPU 1) requests LINK-UP, the master and standby CPUs compare their user programs. If they establish differences, the master CPU updates the user program of the standby CPU.(Refer to Section 5.3.3) 5. After a successful link-up the update starts (see Section 6.2.2). In this instance the master CPU updates the dynamic data of the standby CPU (dynamic data are inputs, outputs, timers, counters, memory markers and data blocks).The contents of the memories of both the CPUs are identical following updating. (Refer to Section 5.3.3) 6. The master and standby CPUs are at RUN following updating. The two CPUs process the user program in synchronism. Exception: in the case of master/standby switch-over for configuration/program modifications. Redundant system mode is only possible if both CPUs are of the same release and the same firmware version. Could you please describe in further detail the CPUs you are using as part of the H-system, and more details on the sequence of operations you tried, and finally any diagnostic message you can find on the CPUs. This would be a great help to us. Hope this helps, Daniel Chartier |
Last edited by: dchartier at: 6/24/2009 6:53 AM |
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