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New to S7, need some help with Hardware Diagnostics

Created by: RWN at: 7/21/2010 1:44 PM (2 Replies)

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7/21/2010 1:44 PM	Rate (0)
RWN Member Joined: 7/15/2010 Last visit: 8/2/2010 Posts: 2 Rating: (0)	Hi guys, I'm new to S7 (and PLCs in general) and have a few questions regarding monitoring hardware faults if anyone could help me out. I've spent a few days now looking through various threads on here (some which have really been of great help) but I'm still a bit stuck! The kit I'm using is a IM151-8 CPU with a few IO modules. I've underlined the questions I've got (in case they get lost in my 'essay' , so if anyone can make sense of what I've wrote I'd really appreciate some possible solutions! I'm looking into monitoring hardware faults in a control interface (similar to WinCC). I'm using OPC so any points to be monitored by the control interface need to be flags in a datablock really. I've currently got OB83 configured to create set a flag if a module is removed by loadingvariables such as #OB83_MDL_ADDR, #OB83_EV_CLASS into the accumulator and comparing them with the values I'm interested in to create flags. This works fine however if I remove more than one module the PLC stops; I take it there's no way to stop this? I've enabled module diagnostics in the PM-E module, however I find that with this enabledthe PLC does report the faultbutstops (whereas if I don't have the module diagnostics enabled it keeps on running). This is obviously a problem as if the PLC isn't running my code isn't being executed andwon't set any flags! Is there any way I can stop the PLC from stopping when any module diagnostics are reported? I'm also having a similar problem with the wire-break diagnostic function on AI modules, if a wire break occurs the PLC stops. I've started writing some code in OB82 to utilise SFB54 and this partially works apart from not all of the code is executed due to the PLC stopping when a hardware fault is reported. I think I can monitor the module diagnostics and successfully set flags if I can stop the PLC from stopping. I realise SFC51 could be of use here, but I'm having a bit of difficulty implementing this (due to my lack of PLC/S7 knowledge) so I'm hoping I can do it using more simplified code. One final question (I promise!), is there any way I can simulatefaults such as a defective module (#OB82_MDL_DEFECT) or a channel fault (#OB82_PNT_INFO)? I'm not sure how I can test that my code works otherwise! I can post up some screenshots or more details of the kit I'm using if necessary. Any advice or links to relevant datasheets would be greately appreciated! Thanks in advance, Richard

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7/21/2010 2:13 PM	Rate (0)
fbelic Silver Member Joined: 2/17/2009 Last visit: 12/1/2020 Posts: 327 Rating: (28)	For first question, look at OB122 (I/O Access Error Organization Block). Best regards

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7/21/2010 4:20 PM	Rate (0)
RWN Member Joined: 7/15/2010 Last visit: 8/2/2010 Posts: 2 Rating: (0)	Have downloaded that and it's sorted it now cheers! Have arrived at another problem unfortunately...if I create a wire break fault on one of the AI modules, I don't get anything reported in the 'STATUS' parameter of SFB54? I'd expect to see '00110' which would translate to a wire break in one of the AI modules (error type taken from AI module manual). Any ideas?

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