How to diagnose a profibus fault?

Hi all,

We have a machine that has about 20 inverters and several other devices attached to it via profibus.

Today we had a profibus fault. None of the drives or other devices would communicate. Every device showed a fault light. The diagnostic buffer was full of errors about Peripheral Words (read and write errors etc).

I've heard about devices that you can plug into networks to pin-point a specific location of a fault. Is there such a device for profibus? Or is there only the information that you get from the diagnostic buffer in Simatic Manager.

We think we've found the fault now. It looks like a linking bit of cable between two devices is faulty or getting interference but, in the future, we would like to be able to diagnose faults with a lot more confidence if possible.

Anyone any ideas?

Cheers

;-)

They make profibus connectors with led lights. This makes chasing down loose wires a lot easier. Here is a link to one.
http://www.dyertech.com/docs/Woodhead/DiagSim/DSUB-Profibus.pdf

Profibus Troubleshooting is really hard .Mostly it because of the connectors or bad wires. You can buy profibus tester which will help you but it will cost you a lot of money

Mark Buskell said:

They make profibus connectors with led lights. This makes chasing down loose wires a lot easier. Here is a link to one.
http://www.dyertech.com/docs/Woodhead/DiagSim/DSUB-Profibus.pdf

Click to expand...

Thanks for the link. That pdf says that the led's for fault finding work for "diagnostics versions only". Does that mean the device has to support diagnostics? ie. it wouldn't work on every device??

bornwild said:

Profibus Troubleshooting is really hard .Mostly it because of the connectors or bad wires. You can buy profibus tester which will help you but it will cost you a lot of money

Click to expand...

Do you know the part number of the tester? Or have you any other information on this?

Many thanks for all your help so far.

;-)

I don't have the slightest ideal what "diagnostics versions only" means.
It's been about 3 years since I used this type with the led on it and I don't remeber exactly who made it. I only did a quick google search for "profibus connectors led" and found this for you. The type we ordered had the led lights like that one but if there was a problem the light would turn to red. I will be glad to send out some emails and try to find the part number if you need futher help. Let me know.

I don't have the slightest ideal what "diagnostics versions only" means.
It's been about 3 years since I used this type with the led on it and I don't remember exactly who made it. I only did a quick Google search for "profibus connectors led" and found this for you. The type we ordered had the led lights like that one but if there was a problem the light would turn to red. I will be glad to send out some emails and try to find the part number if you need further help. Let me know.

P.S.

Terminator monitor indicates if terminator is missing (diagnostic versions only).​

​

S7-400 controller connector has design defects
http://translate.google.com/transla...ttp://www.plc4good.org.ua/view_post.php?id=73

After 6 years of trouble-free operation of Siemens controllers, four series was occasionally lost connection to PROFIBUS-DP line with various devices. After a brief search had found the reason: the crank socket DP on the processor module...

Click to expand...

or
PROFIBUS bus connector defect
http://translate.google.com/transla...ttp://www.plc4good.org.ua/view_post.php?id=72

After 5 years of operation of the equipment began to appear a problem of communication with the controller drives. After a detailed study of diagnostic and test the network device BT-200, was found fault bus connectors Profibus. In particular, in the OFF mode switch on the connector was a transitional floating a few hundred ohms resistance. It was decided to dismantle the bus connector....

Click to expand...

or
sequentially switch the terminator to ON - find the problem area network behind it.

in a similar situation in the past - i have seen Profitrace diagnose the problem within a matter of minutes.

http://www.procentec.com/profitrace2/

I've also seen eratic behaviour when the minimum 1m length between nodes wasn't adhered too.

Fluke's 125 Scopemeter is also a useful tool when diagnosing various Bus systems.

Ditto. My vote for Profitrace.

Thanks for everyone's help on this. Will have a look into Profitrace.

Cheers ;-)

Profitrace

Our company routinely uses Profitrace to diagnose Profibus faults.

Thanks for that Pauly. ;-)