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gdalianis

Problem on S7-400

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Hi, I am having a problem on a Siemens S7-400 PLC. When the rack is powered all the leds of the CPU are lit and remains litted. I can not connect to the PLC with my PC at all. The problem started after I have power down the system and unplug the power from the system for 3 weeks. When I tried to power again the system, the power supply behave very strange with its leds become live and dead rardomly. I suspected that the power supply was defective so I got a new one and raplace it. Now the situation is that the power suply seems OK, at least the 5V and 24V leds is green, but with a red BAF led light on, but all the leds on the cpu is constatly on when I power the system. The Power supply is supplied with 24V and not 220V. I cheched the incoming voltage on the power supply and seems OK (24V), althought I am not sure if the supplied current is also ok. The first PSU is 220V to 24V 37A and supplies power to sensors and relays exept the CPU, is there a way to check if this PSU is OK? I am desperate to start the system, any help would be highly appreciated... thank you

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I think your PLC was Faulty. Anw, try to replace with new power supply and see what happen if the problem is still remain, try to update your PLC firmware.

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I have already replace the power supply unit, do you mean to replace the cpu?

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How was your plc's situation now, the problem have been sloved? Firmware update maybe fix your trouble.

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No I still can not connect to the PLC at all. I am wating for a new CPU, after I place it on rack I will come back with details.

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I think you can update the firmware with mmc card, without plc conection

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After replacing the PSU unit, the CPU itself and also the central rackat our system I finally got to get the system back in operation. But after that a problem has appeared that has almost driven me crazy. I got randomly cpu stops with no obvious cause, all the time with the same error : 494D. After the popup of the error, in order to put the cpu back on RUN I have to switch the power off and reset the cpu after powering it on again...The last week the cpu worked for almost 5 days with no problem and since last Sunday when the problem appeared again, the cpu stops after a random period of time that varies from a few seconds to some minutes. Below is a part of the diagnostic buffer of the cpu: Diagnostic buffer of module CPU 414-2 DP Order No./ Description Component Version 6ES7 414-2XG03-0AB0 Hardware 6 - - - Firmware V 3.0.1 Rack: --- Slot: --- ........ Event 85 of 120: Event ID 16# 530D New startup information in STOP mode Startup prevented by: - Power on necessary - STOP request exists - Cold restart or warm restart necessary Startup information: - Time for time stamp at the last backed up power on - Single processor operation Current/last startup type: - Automatic warm restart after backed up power on Permissibility of certain startup types: - Manual startup not permitted, corrections in parameter assignment, submodule, etc. necessary Last valid operation or setting of automatic startup type at power on: - No startup type/following memory reset Operating mode: STOP (internal) Incoming event 01:19:02.419 PM 09/21/2014 Event 86 of 120: Event ID 16# 494D STOP caused by I/O error No relevance for user (Z1): 940a No relevance for user (Z2): 0000 (Z3): 0000 Previous operating mode: RUN Requested operating mode: STOP (internal) External error, Incoming event 01:19:02.416 PM 09/21/2014 Event 87 of 120: 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: - Automatic warm restart after backed up power on 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: - Automatic warm restart after backed up power on Previous operating mode: STARTUP (warm restart) Requested operating mode: RUN Incoming event 10:55:01.166 AM 09/17/2014 Event 88 of 120: Event ID 16# 1382 Request for automatic 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: - Automatic warm restart after backed up power on 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: - Automatic warm restart after backed up power on Requested OB: Startup OB (OB100) Priority class: 27 Incoming event 10:55:00.044 AM 09/17/2014 Event 89 of 120: 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: - Automatic warm restart after backed up power on 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: - Automatic warm restart after backed up power on Previous operating mode: STOP (internal) Requested operating mode: STARTUP (warm restart) Incoming event 10:55:00.012 AM 09/17/2014 Event 90 of 120: Event ID 16# 5371 Distributed I/Os: end of the synchronization with a DP master Slot of the DP master: 4 Number of distributed stations: 6 Priority class: 23 Incoming event 10:54:59.869 AM 09/17/2014 Event 91 of 120: Event ID 16# 530D New startup information in STOP mode Startup prevented by: - Cold restart or warm restart necessary 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 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: - Automatic warm restart after backed up power on Operating mode: STOP (internal) Incoming event 10:54:59.738 AM 09/17/2014 Event 93 of 120: Event ID 16# 494E Power failure Previous operating mode: RUN Requested operating mode: No voltage External error, Incoming event 10:54:14.644 AM 09/17/2014 Please, I would be gratefull for any help, I don't know how to move on in order to identify the problem. Could some unit be defective? Is it possible to have an earthing problem? Is it possible that I have some problem with the 24v power supply to the PSU? Is there a posibillity that the cpu itself is defective? What is troubling me more is that I can not understand why the problem appears randomly after some period of time and not at the start of the cpu..... Thanks again for your help

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Check the bus connection and interface modules in the distributed I/O. Try to replace also the cable that connect from PLC to IM module if it is exsing in your system. In the order hand, you try to code in OB122 to detect and store error from incoming local data.

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OB122 is already on the cpu, I used it in order to force the cpu to keep running after removing all the cards from the rack. The error is an asychronous error and has nothing to do with the program running on the plc.

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I want to devide my profibus network system with two path which was in single. i want to do it by using a cp 345 module. i need help how to configure it. Regards, chinmaya

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