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A Running PLC "hang" after 1 year+ operation

Created by: YKW at: 5/22/2012 8:50 AM (9 Replies)

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5/22/2012 8:50 AM	Rate (0)
YKW Posts: 21 Rating: (0)	Hi all expert, I have a s7-300 PLC is running well more than a year and last week it seems to be Hang. Details of Incident: The PLC is to control a gas to supply to a plant, there is a local touch screen linked to the PLC and it is also monitored in the control room PC thru ethernet. During the incident, both the local touch screen and control room didnt receive any alarm signal and showing the valves are open for supplying gas. They open the PLC panel and found that there are a lot of red LED were light up. (see attached photo) According the my customer, he first turn off the power to do a power cycling, but after he turn on the power the PLC remain the same error, then he switch the CPU from "run" to "stop" then pull down to "reset" and release it and turn it back to "run". After that the PLC is resumed back to normal without any red LED light up. I have look into the diagnostic buffer, unforturenately, with my knowledge I cannot tell what is the root cause for this incident. Can anyone let me know what is the possibility cause. Thanks. The HWconfig as below PS307 2A CPU 315-2DP DI32xDC24V DO32x24V/0.5A AI8x12Bit AI8x12Bit CP 343-1 Lean Below are the events log file. Diagnostic buffer of module CPU 315-2 DP Order No./ Description Component Version 6ES7 315-2AG10-0AB0 Hardware 7 - - - Firmware V 2.6.11 Boot Loader Firmware expansion A 0.21.0 Rack: 0 Slot: 2 Serial number: S C-A6U660222010 Event 1 of 10: Event ID 16# 4302 Mode transition from STARTUP to RUN Startup information: - Time for time stamp at the last backed up power on - Single processor operation Current/last startup type: - Warm restart triggered by switch setting; last power on backed up Permissibility of certain startup types: - Manual warm restart permitted - Automatic warm restart permitted Last valid operation or setting of automatic startup type at power on: - Warm restart triggered by switch setting; last power on backed up Previous operating mode: STARTUP (warm restart) Requested operating mode: RUN Incoming event 01:54:03.905 AM 10/26/1995 Event 2 of 10: Event ID 16# 1381 Request for manual warm restart STOP due to: Power failure Startup information: - Startup without modified system configuration - No difference between setpoint and actual configuration - Time for time stamp at the last backed up power on - Single processor operation Current/last startup type: - Warm restart triggered by switch setting; last power on backed up Permissibility of certain startup types: - Manual warm restart permitted - Automatic warm restart permitted Last valid operation or setting of automatic startup type at power on: - Warm restart triggered by switch setting; last power on backed up Requested OB: Startup OB (OB100) Priority class: 27 Incoming event 01:54:03.901 AM 10/26/1995 Event 3 of 10: Event ID 16# 4301 Mode transition from STOP to STARTUP STOP due to: Power failure Startup information: - Time for time stamp at the last backed up power on - Single processor operation Current/last startup type: - Warm restart triggered by switch setting; last power on backed up Permissibility of certain startup types: - Manual warm restart permitted - Automatic warm restart permitted Last valid operation or setting of the automatic startup type at power on: - Warm restart triggered by switch setting; last power on backed up Previous operating mode: STOP (internal) Requested operating mode: STARTUP (warm restart) Incoming event 01:54:03.006 AM 10/26/1995 Event 4 of 10: Event ID 16# 5371 Distributed I/Os: end of the synchronization with a DP master Slot of the DP master: 2 Number of distributed stations: 0 Incoming event 01:53:50.286 AM 10/26/1995 Event 5 of 10: Event ID 16# 4358 All modules are ready for operation Operating mode: STOP (internal) Incoming event 01:53:48.194 AM 10/26/1995 Event 6 of 10: Event ID 16# 4357 Module monitoring time started Operating mode: STOP (internal) Incoming event 01:53:42.768 AM 10/26/1995 Event 7 of 10: Event ID 16# 4300 Power on backed up Previous operating mode: No voltage Requested operating mode: STOP (own initialization) Incoming event 01:53:41.337 AM 10/26/1995 Event 8 of 10: Event ID 16# 494E Power failure Previous operating mode: STOP (internal) Requested operating mode: No voltage External error, Incoming event 01:53:19.512 AM 10/26/1995 Event 9 of 10: Event ID 16# 5371 Distributed I/Os: end of the synchronization with a DP master Slot of the DP master: 2 Number of distributed stations: 0 Incoming event 01:50:48.315 AM 10/26/1995 Event 10 of 10: Event ID 16# 4358 All modules are ready for operation Operating mode: STOP (internal) Incoming event 01:50:46.211 AM 10/26/1995 Attachment iPhone 1081.JPG (196 Downloads)
YKW Posts: 21 Rating: (0)
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5/22/2012 9:10 AM	Rate (0)
manmeet Gold Member Joined: 1/3/2006 Last visit: 2/19/2024 Posts: 726 Rating: (71)	Hi, From photograph it appears that all LED's of CPU is continusously ON, in that case you need to reaplce it.

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5/22/2012 10:02 AM	Rate (0)
YKW Posts: 21 Rating: (0)	Hi Manmeet After the incident, the same CPU is running fine for more than a week already. Do you mean I should replace a new CPU? Is the existing CPU is dying and the same incident will happen again? I couldn't reach my customer now, so I am not sure whether all the LEDs are continuously ON or some are blinking. If replacing the CPU can solve the problem and prevent the same thing to happen again then I will suggest to my customer to replace a new CPU card. Thanks.
YKW Posts: 21 Rating: (0)
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5/22/2012 10:06 AM	Rate (0)
Wizard Diamond Expert Joined: 4/24/2006 Last visit: 9/10/2024 Posts: 8736 Rating: (1167)	Hello YKW, The diagnostic information you give, is not enough. When you put CPU in STOP, you will get 100 entries in diagnostic buffer. (You can even export them to a file) Then you can perhaps find the reason for problem. Best regards, Wizard

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5/22/2012 10:37 AM	Rate (0)
Wishme Experienced Member Joined: 8/20/2009 Last visit: 5/21/2024 Posts: 80 Rating: (5)	Dear YKW, I doubt that there was some disturbance in Main supply to thepanel (i.e., main incomer, feeder, etc.)or Earthing of the panel. Pls check with your customer. Due to this, therecould besome alteration in thesystem memory, load memoryor firmwareofthe CPU. Memory of any electronic system is very sensitive to the power fluctuation!!!!! Tell your customer to be carefull with any power related work where the component like PLC, drives are connected. Its always good habit to turn off the PLC when working with power or puting high load on the plant wide supply i.e., welding machine. VishP.
	Vishme. Hang on...may be we drop a step before Success.
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5/22/2012 10:39 AM	Rate (0)
YKW Posts: 21 Rating: (0)	Hi Wizard, Thanks for your info, I will go back and export the file again.
YKW Posts: 21 Rating: (0)
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5/22/2012 3:46 PM	Rate (0)
Aret Posts: 2348 Rating: (264)	Dear YKW, all LEDs blinking also states, that CPU need to be replaced. Yes, it can work now, but until you discover the reason of such reaction you can't say CPU is working properly. If you didn't find any grounding problems etc. (please see posts above) you should assume CPU is faulty.
Aret Posts: 2348 Rating: (264)
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5/23/2012 12:30 PM	Rate (0)
YKW Posts: 21 Rating: (0)	Dear all, First of all, I would like to thanks all of you for the information and suggestion provided. As concluded the information above, I think the best way is to change a new CPU card and during CPU replacement, I will check all the grounding point and also to ensure the firmware of CPU is the latest version. Meanwhile, can I have a better understanding of the diagnostic buffer I exported today? I have set the CPU to stop mode to export the file, I think Event 14 is the error log for this incident. (Kindly find attached diagnose file) and also below are the description of the Event 14. Event 14 of 100: Event ID 16# 4550 DEFECTIVE: internal system error No relevance for user (Z1): f102 Previous operating mode: RUN Requested operating mode: DEFECTIVE Internal error, Incoming event 07:41:42.536 AM 10/25/1995 Does it mean the CPU is defective? Thank you! Attachment Diagnose_N2O#2_offline.zip (129 Downloads)
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5/23/2012 2:13 PM	Rate (0)
Aret Posts: 2348 Rating: (264)	Very likely CPU is defective. Please send your buffer via Support Request, they can "decode" things like (Z1): F102. Also - when you send diag buffer please send in 2 formats - human-readable AND hex-format, as it contains more info (you can change view by pressing button in Diagnostics Window).
Aret Posts: 2348 Rating: (264)
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5/24/2012 1:46 PM	Rate (0)
Marko Bursic Platinum Member Joined: 9/8/2009 Last visit: 7/17/2023 Posts: 1410 Rating: (152)	Your PLC is possibly blown, but maybe is not. I have seen CPU in all LED blinking condition that worked fine for years. IMO your PLC get some voltage spike, check wether analog modules have galvanic isolation or not - you will find in specs from operating manual of modules. Check if the MANA connection is present and tied on ground potential. If you have solenoid valves or electric brakes pay attention if they have surge protection devices like varistors or freewheel diodes on them, if not this can cause spikes when disengaging them.

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