3/27/2020 12:22 PM | |
Posts: 50 Rating: (0) |
Sir, I want know how to write program for ob 86 in rack failure time. For that purpose I want to generate rack failure fault after I write program for ob 86. |
3/27/2020 1:00 PM | |
Joined: 9/27/2006 Last visit: 10/17/2024 Posts: 12289 Rating: (2687)
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Hello RmnChowdary; All the basic finctioonalities of a diagnostic OB are in its local data, internal variables that collect data for the diagnostic buffer. When a remote rack fault is detected, and an empty OB 86 has been created and downloaded to the user program on the CPU, data collected by the OB 86 local data is read by the diagnostic buffer, so the source of the fault is detected by the CPU's OS (with much more details than is available without the OB 86). Also, without the correct diagnostic OB for a specific fault type, the CPU will simply go to Stop mode, with diagnostic LEDs active (SF/BF). If the correct diagnostic OB is found in the user program, the CPU will use the interrupt by the OB to collect data, then return to the program. In other words, the CPU will continue running on the presence of a fault, but with active LEDs (to tell you something is wrong). For more information on S7 OBs, and more precisely diagnostic OBs, please refer to chapter 1 in the System and Standard Functions manual (written for S7-300 and S7-400 CPUs, but chapter 1 is quite valid for all S7 families). https://support.industry.siemens.com/cs/ww/en/view/109751826 You can always program some code in a diagnostic OB, but in most cases that is not necessary. If you feel the need to do so, make the code short and easy to execute, so that it does not extend he interrupt time of the OB: activating a bit, calling an external function... Hope this helps, Daniel Chartier |
Last edited by: dchartier at: 03/27/2020 13:01:27 |
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