S7-400 DP fault problem

Hi.
I have some problem about S7-400 PLC.
In my project have 11 expansion rack consist of 6 et200s and 5 et200m. Problem is when one of et200m power down all expansion rack cann't work. Bus fault is show and all of I/Os. card cann't work.
Thanks you.

You need to go online to the processor.
Check the diagnostics on the CPU.
How many items are on the profibus network
You may not have all the nodes listed.
If the machine has fibrre optic nodes - it may be one of thse cables.

If the one ET200M that causes the fault is the very last one in the daisy-chain, then the problem is that the bus termination disappears when power is off.
The remedy is to finish the daisy-chain in an active bus terminator.

Thanks you for your answer.

I active bus terminator on the last of network already.
In my diagram network is
S7-400(2)=>ET200M(15)=>ET200M(10)=>ET200M(9)=>ET200M(8)=>ET200M(7)=>ET200S(20)=>ET200S(19)=>ET200S(18)=>ET200S(17)=>ET200S(16)=>ET200S(15)
In this case ET200M(9) address 9 is power down. Bus fault is show and all of I/Os. card cann't work.

Could you post a scrn Prn of the Hardware setup please.

Also the bus fault may be due to the at200m(9) being powered down.

According to the info you have an ET200M (15) and an ET200S (15)
That can't be right.

What baudrate ? And what is the distances between all nodes ?

Hardware config. follow this picture. Baudrate = 187.5 kb/s.

Distant between node is on the picture.

In this case ET200M(14) is power down. Bus fault is show and all of I/Os. card cann't work.



I'm sorry about DP address.

The attached picture doesnt show in my browser.

To JesperMP
I post my picture on web imageshack.us and my browser is firefox.

url link => http://imageshack.us/photo/my-images/687/pcu6.jpg/

Not all the nodes are shown in the picture with the distances.
The node 9 that causes the problems is not shown.
And the sequence is different to the one you posted in post #4.
You can rearrange the visual layout in the HW Config to reflect the actual sequence of nodes.

The sequence and all DP address on comment #4 is wrong. (my bad)
The real config is picture on comment #9

At 187.5 kpbs, 180 m all together should be no problem.

I have seen some info about that very short connections should be avoided.
So you may try to exchange the 0.5 m and 1 m cable bits with 2 m.

Is the termination on in the connector in the CPU ?

If node 14 is off, then you get a BF on the CPU, but are you sure that all the other nodes also get a BF ?

Check that all cables and connectors are OK.

If this does not reveal the cause, you may have to buy or rent a profibus analyser, such as Profitrace.

iant said:

You need to go online to the processor.
Check the diagnostics on the CPU.

Click to expand...

What about posting the diag?

Kalle

Some message show on diag.

Event 1705 of 3000: Event ID 16# 38B4
I/O access error when transferring the process image to the output modules leaving state
P area, byte access, access address: 120
process image partition no.: 0
not user relevant(Z1): 2943
Requested OB: Program execution error OB (OB85)
Priority class: 25
External error, Outgoing event
02:09:47.590 PM 06/21/2011

Event 1707 of 3000: Event ID 16# 38B3
I/O access error when updating the process image input table leaving state
P area, double-word access, access address: 764
process image partition no.: 0
not user relevant(Z1): 2942
Requested OB: Program execution error OB (OB85)
Priority class: 25
External error, Outgoing event

" Message I/O access error is show all I/O address. I have transfer OB85 already. But in diag it say request OB85."

Event 1706 of 3000: Event ID 16# 38C4
Distributed I/Os: station return
Address of the affected DP slave: station number: 3
DP master system ID: 1
Log. base address of the DP slave: Input address: 16375
Log. base address of the DP master: 16383
Requested OB: Rack failure OB (OB86)
Priority class: 25
External error, Outgoing event

" Message station return is show all station. I have transfer OB86 already. But in diag it say request OB86."

angyoshin said:

I have transfer OB86 already. But in diag it say request OB86."

Click to expand...

If the OB86 was lacking, the CPU would stop on this event.

Could you please make some clarifications for a slow thinker like me:

1: When you depower N14 all other nodes on the bus fails with BF?

2: If you unplug the Profi on the depowered N14, does the other nodes come up again?

3: If yes on question 2, there must be something wrong with your cabinets' earthing potentials.

Kalle