Siemens PLC 412 EXT Fault & Bus2 Fault

Help from experts
Siemens PLC 412 is connected with 12 stations through profibus dp.PLC showing external fault (red led steady) and bus2 fault (red led blinking) and some stations showing run ok and some stations are showing Bus fault
For trouble shooting purpose I checked the all stations probibus cables and its connectors are found good.and i used step 7 V5.3 program to rectify the problem and i found plc status is showing error and in the hardware somes slash mark (/)on some stations and stations not avilable and some stations are ok
How i can fix the like this problem

Chandrashekar said:

Help from experts
Siemens PLC 412 is connected with 12 stations through profibus dp.PLC showing external fault (red led steady) and bus2 fault (red led blinking) and some stations showing run ok and some stations are showing Bus fault
For trouble shooting purpose I checked the all stations probibus cables and its connectors are found good.and i used step 7 V5.3 program to rectify the problem and i found plc status is showing error and in the hardware somes slash mark (/)on some stations and stations not avilable and some stations are ok
How i can fix the like this problem

Click to expand...

Hello Chandrashekar;
When you see the red slash (/: icon for defective station) over a Profibus station, you are opening the HWConfig editor in Online mode, correct?
Double-click on each station that shows the red slash and you will open the diagnostic buffer for this paricular station; this will contain diagnsotic information that should point you to the cause of the problem. This also works for the CPU, by the way, which shpould have the same icon if it shows SF and BF2 LEDs.
The contents of the diagnostic buffers can be saved 9as text), and you could show us the contents (or part of it) so we can help you understand the messages, if they are not clear.

Now, a good ressouce for you at this time would be the "Programming with Step 7" manual. On your computer (where Step 7 is installed) you should find a copy of this manual for v. 5.3 (under Start-­Simatic-Documentation). If you can't locate it, download this version for Step 7 5.5:
http://support.automation.siemens.com/WW/view/en/45531107
Open the chapter on Diagnostics, and use the information there to locate your faults.
Again, attaching the contents of the diagnostic buffer that relate to these fauls will allow us to help you out.

Hope this helps,
Daniel Chartier

A never ending story....


Have a look in this old thread, lots of tips:

http://www.plctalk.net/qanda/showthread.php?t=26429&highlight=profibus

Kalle

Thaks for yours quick replys dcchatier and KalleOlsen
Yes your right i was in online mode and i will look at that messeage and forword you for continue technical suport

hi dcchatier and KalleOlsen
I attached the picture of stations and plc error status
Profibus as connected as belows
plc
Station # 11
Station # 12
Station # 13
Station # 5
Station # 21
Station # 25
Station # 41
Station # 42
Station # 35
Station # 22
Station # 23
Station # 24
You can see in picture some stations are not working some stations intermediatly.still problem is not traced i looking for your valuable help

Did you read the thread I gave you?

If not, spend one hour and read this document:

Profibus installation Guidelines ? ( http://www.profibus.com/downloads/ in the section "Installation Guide".


Kalle

If you are sure the bus connection is OK. Then you can also check you configration is OK or not, single click NOT online component Ctrl+D,check module information. In identification tag, if you get some iformation from that menber, that mean you configration is dismatch with actual situation on sit. Then you correct you HWconfig.

Hi hill831017
I think there is not required to check the configaration and correct the hardware configaration, this system was working since more then 8 years.
I changed the stations probibus all connector with new one and also checked the profibus cables continuty and ground fault, In the bus some of the starting stations and some of end stations are showing ok but middle of some stations are showing module not avilable.
I need the support for trouble shoot the problem

Advise. Do you have diagnosic repeater existing in you system? If yes then you could use SFC103 to make Topology test for your Profibus.
If not you can try to get a BT200 handhold device to test you profibus.
It's a advance test better than you only check the the connection.

Otherwise you have to check whole cable path there might be problem.
Cause I met once cable in between two device was twisted or bite by mouse.
It's also good if you can send the bus structure, then we can locate possible position of "wire break".

Hi Mr,hill831017
Thanks for your support
I am attached the drawing of the bus connection, in drawing 25A is station # 35 ( Typing mistake, there is no station # 25A)

Bus is started from PLC 414-2DP and connected to station # 11 and bus is ending on station # 24 (You can in drawing for full bus connection

Bus is ok untill satation # 21 after that 25, 42, 41, 35 is not ok after that all 3 stations 22,23,24 are ok

diagnosic repeater different software or it is included in step 7 program

For a large plant, and with VFDs, a good earth connection that is well distributed to all cabinets is really critical.
Also the motor cables from the VFDs absolutely must be screened and well connected to earth.

I notice you have a couple of operator panels in the profibus net. Are they included in one single STEP7 project ? As a test, you can try to disconnect the panels.

Apart from that, a Profibus tester is a really good thing to have. You can buy or rent it. Given the size and complexity of your plant the cost for the tester is not so bad. We have used the "profitrace" with success.

ok, i know that type of plant, it looks identical to one of ours, you said you changed all the profibus plugs, check to make sure the in and outs are correct first, and the end ones are terminated via the switch.

Here comes the probable reason why you are having this reason, have you changed one of your Lenze drives?. i am sure you have, did you make sure the earth on the motor cable is good? Campen love to run motor and profibus cables in the same trunking. Why i am saying it is more than likely the motor cable,is because i had exactly the same problem, everything would work, until certain drives were started, i started losing nodes.

The nightshift electrician had his ears boxed when i found that one

We didn,t change any lenze servo drive or servo motors, In bus end of node(node # 24) pofibus connector is on mode (not looped for next node)Node # 25 is sometime giving some errors, can correct with node on/off switch. It is Siemens Simatic ET200L-SC,Part # 6ES7 138-1XL00-0XB0,Let me know if there is a any way to check the node on by one, to confirm that part is ok

Chandrashekar said:

Let me know if there is a any way to check the node on by one, to confirm that part is ok

Click to expand...

Yes this is sooo simple that I indeed hope I misunderstood your question:

Switch the termination ON on the node you want to check. Pull out all the plugs between the node and the busmaster.

Kalle