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About QVZ, ET200 Diagnostic Function, OB23/OB24

Created by: spm_cpl at: 10/28/2010 11:20 AM (6 Replies)

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10/28/2010 11:20 AM	Rate (1)
spm_cpl Posts: 25 Rating: (1)	Hello~ Thanks your time for reading. My questions is: 1. I want to know, How does ET200 Diagnostic Function work? How is it to know which ET200 station is offline (or something...)? and 2. Wha't different between OB23 and OB24 ? (Maybe you can explain to me Periphery I/O and Process Image I/O more detail. I did study the maunal, but not very understand at all.) Our PLC occur QVZ recently. Originally, we use ET200 Diagnostic Function to find out which stastion offline. And then, I add some code in OB23 and OB24 to get which I/O cause QVZ while QVZ occuring. (The code just do saving the ACCU1 and ACCU2 while PLC running OB23/OB24). I find something strange, the ET200 Diagnostic show me offline station that it's I/O is different the OB23/OB24 catch. So, I wonder how does ET200 Diagnostic work ?? Thanks your answer. Sorry my poor English.
spm_cpl Posts: 25 Rating: (1)	Last edited by: spm_cpl at: 10/28/2010 11:22 AM
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10/28/2010 3:33 PM	Rate (1)
safety4ever Experienced Member Joined: 12/5/2006 Last visit: 2/6/2024 Posts: 73 Rating: (4)	OB23 is used to detect errors when they are related to the user program ie. sometimes you may be accessing analog cards for example using L PW xxx or T PWxxx and atsome point those modules are not ready to respond for some reason either module fault or voltage missing so the instruction PW in your program would trigger the OB23. In other situation where you use an IM 308B/C as a profibus master to some drives or ET200 and the IM 308 is loosing one of the stations that the CPU is trying to read in this case a QVZ is initiated and also OB24 would be triggered. Also as far as I remember the accumulator 2 low byte would hold the address of the module that initiated the fault in hex value. There are also instances where the Profibus diagnostic is strictly done with FB192 in S5 programs for more information you could use this manual CH 7 to understand more about this block if you are using IM 308C http://support.automation.siemens.com/WW/view/en/21667381 Regards

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3/4/2011 4:58 PM	Rate (0)
spm_cpl Posts: 25 Rating: (1)	Thanks your answer. This issue cause our PLC STOP now, this is not good... I found the reason for PLC STOP was OB24 QVZ. And the CPU948 manual say : OB24 is "Timeout (QVZ) when updating the process image and transferring interprocessor communication flags." So, what 's "process image" ??, Is it in CPU ?? Should I replace CPU card ?? I think I really need your HELP to solve this problem. BTW, Our PLC has : 923C x 1 948 x 1 928 x 1 IM308B x 1 Please tell me any information about PLC STOP by OB24. Thanks a lot !!
spm_cpl Posts: 25 Rating: (1)
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3/7/2011 1:33 PM	Rate (0)
safety4ever Experienced Member Joined: 12/5/2006 Last visit: 2/6/2024 Posts: 73 Rating: (4)	Hi Sorry for the late answer, but if your CPU is falling in stop mode there should be an STP in OB24, normally the presence of OB 24 should prevent the CPU from stopping. If this is the true cause of stop of the CPU you should be able to put an FB in OB 24 to read ACC 1 and 2 normally the address that causes the STOP should be recorded in ACCU2 in OB 24. Now in your situation it might be tricky as you have 2 CPU's in most cased with Multi processors if one CPU is stopping it causes the other CPU to stop as well. So this would require collecting as much as possible information from the 2 CPU's. First you need to see the address that causes the fault by building a code that reads ACCU 2 in OB 24, second you have to read the ISTAck of each CPU at the moment of the stop, once you get this, you would have to verify DB1 of Each CPU to see this address if it belongs to CPU 1 or CPU 2. A process image is an address that is declared in the area 128 and up normal if it is addressed directly it is designated by PW or PY ( for bytes) or PD for Double word it extends from PW 128 to PW 254 it is mainly used for analog modules or sometimes for profibus (remote I/O) addresses either Drives PZD's or PKW's or regular analog cards in rare situations also IP card (intelligent peripheries). I would not think it is CPU issue check your profibus network most probably one of the nodes could be causing troubles, in some rare situations. I also saw situations where a bad back plane on the main rack could cause this specially with old Racks 6es5 155... or 6es5 135.... Wish you good luck with your problem,

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3/8/2011 4:26 AM	Rate (0)
spm_cpl Posts: 25 Rating: (1)	Hi~ safety4ever. Don't be sorry. Thanks your help a lot !! I taken off STP from OB23 & OB24, but it still go to STOP (sometimes...). And I have already put the FB in OB23 & OB24 to catch ACCU1 & ACCU2 content when QVZ occur. My FB code and error information below : CPU948's code: L DH 000E F044 LIR 1 T DW 0 L DH 000E F045 LIR 1 T Dw 1 and I got: 000F F04B when OB24 CPU928's code: T DW 0 TAK T DW 1 and I got 1E23 F005 when OB23 and 1E25 F035 1E26 F04B when OB24 and about ISTACK, I didn't see anything indicate me which address cause QVZ, although those bits have been in DB1. So do you have any idea, let ISTACK show me address ?? Which part should I set or check ... (BTW, Our PLC have COR923 + CPU948 + CPU928 + IM308B + ET200U) Do you know (maybe) any setting at IM308B could triger ISTACK showing QVZ address ?? I have replace some ET200U wire between stations (not all wires yet) and some ET200U Unit (6ES5318-8MB13 & PS931), but QVZ still occur. Should I replace IM308B ?? And last thing is .... Our rack is 6ES5-155U !!!! And replace rack is big huge work ... So maybe you can point me "when" I need decide to replace the rack ... Thanks your help ~. Thank a lot !! Bset Regard ~
spm_cpl Posts: 25 Rating: (1)
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3/8/2011 1:04 PM	Rate (0)
safety4ever Experienced Member Joined: 12/5/2006 Last visit: 2/6/2024 Posts: 73 Rating: (4)	spm_cpl Hi~ safety4ever. Don't be sorry. Thanks your help a lot !! I taken off STP from OB23 & OB24, but it still go to STOP (sometimes...). And I have already put the FB in OB23 & OB24 to catch ACCU1 & ACCU2 content when QVZ occur. My FB code and error information below : CPU948's code: L DH 000E F044 LIR 1 T DW 0 L DH 000E F045 LIR 1 T Dw 1 and I got: 000F F04B when OB24 CPU928's code: T DW 0 TAK T DW 1 and I got 1E23 F005 when OB23 and 1E25 F035 1E26 F04B when OB24 and about ISTACK, I didn't see anything indicate me which address cause QVZ, although those bits have been in DB1. So do you have any idea, let ISTACK show me address ?? Which part should I set or check ... (BTW, Our PLC have COR923 + CPU948 + CPU928 + IM308B + ET200U) Do you know (maybe) any setting at IM308B could triger ISTACK showing QVZ address ?? I have replace some ET200U wire between stations (not all wires yet) and some ET200U Unit (6ES5318-8MB13 & PS931), but QVZ still occur. Should I replace IM308B ?? And last thing is .... Our rack is 6ES5-155U !!!! And replace rack is big huge work ... So maybe you can point me "when" I need decide to replace the rack ... Thanks your help ~. Thank a lot !! Bset Regard ~ It seems you have got some errors addresses already, and yes you have an older Rack I have heard sometimes those racks cause some problems but before touching the rack I would watch those addresses you got from OB24 and OB23 it seems they point to some I/O addresses what you could do is note down those addresses every time you have an error and see if the results are consistent every time if they are then most probably of those addresses or all or them are cause the problem. You should also note their location are they in the main rack are they on a ET 200 U etc... normally the way to calculate the rack you can check in the 928B and 948 manual what do those HEX code mean. For example if you see the 928 manual 1E23 F means Timeout (QVZ in the user program when accessing the peripherals yyyy = QVZ address so filter everything from this value except the last 3 digits convert those to DEC and that would leave you with address 5 same with the 2 other errors and the 948 one. 4B for example is address 75 which is common between the 2 CPU (most probably shared in DB1) and so on. I do not remember too much about the 308B diagnostic tools it has been a while It may also have a BF light that comes if one node is lost or if one of those addresses belong to a profibus slave on the network. If you have a spare one you could also replace it just a matter of switching the module and replacing the memory card to the new one but I doubt it is the IM otherwise you would have had complete network outage.
	Last edited by: safety4ever at: 3/8/2011 1:05 PM
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3/14/2011 7:07 AM	Rate (0)
spm_cpl Posts: 25 Rating: (1)	Dear safety4ever : Last week, we check the ET200 network line resistance. And we found there have three terminal resistance is ON at three stations (Total line resistance is 88 ohm). After correcting it (Total line resistance is 220 ohm), I don't see any QVZ occur at the monitor code in one week. So maybe we solve this problem for now. Anyway, thanks your help. Best regard
spm_cpl Posts: 25 Rating: (1)
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