s7 300- ET200M, SF AND BF BLINKING

goko2rock · Apr 17, 2011

Dear Sirs,
I am in a great trouble. 2 weeks before my plant system configured with 1 master and 2 slaves. one of the slave node (ET200M) shows error SF and BF blinking. when i checked with diagnostic buffer it said module not found. i exchanged the respective modules still the faults were not cleared. i then interchanged the modules arrangement (analog,digital,analog,digital) and the fault disappeared. again now the same faults is coming. i don't know what to do now. i check the programs it have necessary OB'S and baud rate is also ok. i changed the communication cables. changed the 24v supply.

some times the fault gets cleared and machine runs. sometimes it does not. please some one help me.

its very very very urgent...

JesperMP · Apr 17, 2011

To me it sounds like cable problems.
Investigate all the profibus connectors.
Investigate the Hardware Diagnostics in STEP7.
Check if there is an equipotential earth between cabinets.
Check that the earth is good enough.

If that does not reveal anything, you may consider to buy or rent a Profibus tester.

goko2rock · Apr 17, 2011

profibus tester..!!what to do with that. ok i tried changing profibus cable it self..!!
still the problem is not solved.
i need a very urgent help from some one.. please i request everyone here to suggest a solution..

regards,
goku

KalleOlsen · Apr 17, 2011

JesperMP said:
To me it sounds like cable problems.
Investigate all the profibus connectors.
Investigate the Hardware Diagnostics in STEP7.
Check if there is an equipotential earth between cabinets.
Check that the earth is good enough.

If that does not reveal anything, you may consider to buy or rent a Profibus tester.

Did you check the earthing? If not, do a test and connect the cabinets PE rails vith a bigger PN, f.x 10mm2. Check that the 0V is earthed to signal earth and that the signal earth is connected to PE.

Kalle

JesperMP · Apr 17, 2011

When you changed the cable did you change the connectors ?
I have experienced bad connectors.

Did you check how the cable is terminated in the connectors ?
Many many times regular electricians have no clue how to connect the shield in the connectors.

As said before, check the earth.

You can also tell us more details about your installation, distances, baudrate.

goko2rock · Apr 17, 2011

Yes when i removed the cable i changed the total connector also..and as far as earth is concered its done . i checked earting 0v too. again the same fault. there are interconnected system. one more ET200M module and 315 dp no fault appears there. its very strange. when i inter changed the module(analog,Digital,analog, digital) the fault disappeard for a week.
how is that possible..
now when i try interchanging its not working...

oopse.. am realy F!@#$d up..!!

JesperMP · Apr 17, 2011

I recommend you buy or rent a Profibus tester.

We used this one:
http://www.procentec.com/profitrace2/

NB. How about answering the rest of the questions ?

goko2rock · Apr 17, 2011

yes i am testing those thing...this is a process automation plant. bcz of this problem everything is stopped. and idiot me has no clue.

goko2rock · Apr 17, 2011

tested what ever said above still sf and bf flashing. at times fault clears but comes back after few minutes. ..

JesperMP · Apr 17, 2011

Can you confirm this:

JesperMP said:
Check if there is an equipotential earth between cabinets.

And answer this:

JesperMP said:
You can also tell us more details about your installation, distances, baudrate.

You are way over three strikes, but I give you one more chance.

goko2rock · Apr 17, 2011

my baud rate is 187.5kbps .

please the image.

http://www.facebook.com/photo.php?f...50116149173278.317434.691603277&type=1&ref=nf

you will get a idea about my configration.

i didt get what do you realy mean by equipotential earth.. earthing is same equal in potential between cabinet.

JesperMP · Apr 17, 2011

There MUST be an equipotential earth between cabinets.
The common earth going to a central earth point is not enough.

I dont use facebook.
The image link is dead.
Since I cannot see your layout, I cannot say any more.

goko2rock · Apr 17, 2011

well i will check tht out. by the by can i add you in skyp ,msn or yahoo..

my skyp name : gokulnath.g
msn: [email protected]
i will b greatful if u dont mind adding me

regards,
goku

KalleOlsen · Apr 17, 2011

You could use OLM's to get a galvanic separation.
Or every profi-maintaner should have a couple of these in the pocket and a fiber dropline around the neck:
http://www.helmholz.de/prod,80_107_109.html
Select Fiber Optic Converter and go for Optopus.

Kalle

Edit:

JesperMP said:
I dont use facebook.

And I thougt I was the only fossile member here

cjd1965 · Apr 17, 2011

Hi
What about going online within the hardware config and seeing what is shown (or not) as a crude indication of the available profibus network

I also agree with previous comments ref profibus connectors.. and have you checked basics like only the end profibus plugs are fitted with resistors (usually a slider set to ON)

cheers

s7 300- ET200M, SF AND BF BLINKING

goko2rock

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