8/23/2011 3:36 PM | |
Joined: 10/7/2005 Last visit: 10/19/2024 Posts: 3024 Rating: (1054)
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Hello deliberately restarting an S7-300 once a day to overcome issues with another controller "misbehaving", now that's what I call "creative thinking". WhileI'd personally rather fix the underlying problem with the "misbehaving" controller, you can force a programmatic restart with the following "trick" (even though this will cause a Power off restart, a 300 always does an OB100Warm restart after power off/on): 1.) Find a free DQ and use it to drive a relay whichtakes out the CPU's 24V (or the power supply's 240V). 2.) Write some logic to set a bit once a day (e.g via usage of time of Day interrupt or script from SCADA etc.). 3.) Use this bit to drive the DQ. 4.) What happens then is: DQ ON, Relayopens and kills power to the CPU, all DQ's switch off, power comes back on, PLC restarts. 5.) Reset the bit in startup OB 100. I hope this helps, but nonetheless encourage you to rethink this rather brute solutionwhich simply deals with the symptons instead offixing the real problem. |
Cheers |
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This contribution was helpful to1 thankful Users |
8/23/2011 5:04 PM | |
Posts: 947 Rating: (45) |
Hi viki_bum. Your need additional CPU (PLC). see SFB20 to Changing a Remote Device (as sample CPU) to the STOP State with SFB 20 "STOP" and SFB 19 for Initiating a Warm or Cold Restart on a Remote Device or SFB21 Initiating a Hot Restart on a Remote Device. You also can use the relay to switch off and switch on the power of your PLC. |
8/24/2011 7:24 AM | |
Posts: 37 Rating: (2) |
All exeperts r asking why u want to give restart ? what is the exact problem for which u want to give warm restart? |
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