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Step Address Counter and OB 170

Created by: jameel at: 8/7/2013 6:55 PM (3 Replies)

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8/7/2013 6:55 PM	Rate (0)
jameel Posts: 7 Rating: (0)	Hi,I'm trying to write a function that will capture the BStack data for a customer who is experiencing randomn PLC stops. The customer has a S5 928 CPU and according to the manual i can capture Bstack entries using OB 170. It would be much simpler for the customer to just take a screen capture of the Bstack entry when the problem occurs, but they do not have the S5 software on hand or the expertise to use it at the remote location. They just go back to run mode.So i plan to add OB 170 call in their existing software. The problem i'm having when doing some testing in lab is that I only get the SAC (absolute return address) when using the OB 170 call. How can i use this information to determine which fb/ob/pb is being called when the stop occurs. Please see atatched screen shots from my testing.on the leftis the actual bstack entry on the plc, and on the right shows the data gathered using OB 170. Is there a way i can determine the block type and number from the Return address that i obtain using OB170? For instance, how does 53F7H correspond to OB20 address 0002? Is there some sort of mapping from return address to Ob,Pb, Fb numbers? Attachment C:\Users\shaikhj\Documents\Bammel Work\Enterprise\Bstack.jpg (89 Downloads)
jameel Posts: 7 Rating: (0)
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8/7/2013 10:05 PM	Rate (0)
dchartier Grandmaster Joined: 9/27/2006 Last visit: 10/4/2024 Posts: 12283 Rating: (2685)	Hello Jameel; I am afraid I have no direct experience with OB 170 Bstac read function in the S5 CPUs.. But I found the following description of the function that could probably guide you in decyphering the resulting DB. See the attached file. There does not seem to be an easy way to associate the values in the DB (as shown in the attachment) to the calling block type and number. These pages were printed from the following link: Siemens S5-135U CPU 928B - Siemens Industry Online Support Hope this helps, Daniel Chartier Attachment C:\Users\chard2\Documents\SForm\OB170 description.pdf (249 Downloads)
	Last edited by: dchartier at: 8/7/2013 10:22 PM Last edited by: dchartier at: 8/7/2013 10:13 PM
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8/7/2013 11:58 PM	Rate (0)
jameel Posts: 7 Rating: (0)	I followed that example in the manualto copy the values into DB200 that i showed you in the atachment. What i need to know is how to interpret the SAC entries that I get as a result of calling OB170 to give me a PB, FB, FX that casued the particular entry to begin with. Thank you for your help.
jameel Posts: 7 Rating: (0)
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8/28/2013 9:26 AM	Rate (0)
LXG Posts: 33 Rating: (0)	Hellojameel I would check the S5 code on the addresses gave by B-stack. For example: blockFB250 address 52E7 or block FX0address 54C7.
LXG Posts: 33 Rating: (0)
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