Profibus Connector

Hi All,

How to check profibus connector if it is good or not ?

What I make, and I don't know is this the correct check or no:

- Check that Channel A "A1, A2" has resistance.

- Check that Channel B "B1, B2" has resistance.

- Check that Channel A and Channel B no have any continuity together.

Is this correct ?

Another question:

If 1 channel not good, will the connector work without problem ?

Hello crocodile;

I remember studying  this article from SMAR  about Profibus-DP network troubleshooting.

There are sections in it that discuss testing the connector with a multimeter; see the attached screenshot.

http://www.smar.com/en/technical-article/tips-for-trouble-shooting-on-the-profibus-dp

Hope this helps,

Daniel Chartier

Edit: for your second question, look at the diagram at the bottom of the article, showing the schematics of the termination résistors. I would say that if a channel is not working you might have trouble with the termination being properly powered up. Whenever a Profibus connecter is found defective, we discard it and try to have it replaced by the seller (if it a new one).

D.C.

If connector is defective, shall I get a BF at my CPU ?

Here is the story:

For about 1 week, I've a problem in one machine.

Motor drive (ABB) suddenly stopped, without any alarm.

I doubt in so many things.

But, at the last, we found 1 profibus connector of a distributed I/O, defective. "1 channel not showing resistance if we put the connector in the ON position"

I didn't check network with a profibus tester.

I checked only in simatic.

How this distributed I/O was working with 1 channel ?

Why I didn't get a BF at the CPU ? "315-2DP"

-----

Edit:

How I check the connector:

- Out both profibus from it.

- Put its switch to ON.

- Check resistance between A1 & A2. "Good, I didn't remember how much resistance"

- Check resistance between B1 &B2. "Not good, not showing any continuity"

- Check resistance between A Channel and B Channel. "Not showing any continuity"

Is this check is correct ?

Hello crocodile;

I cannot say why your CPU 315-2 did not catch the error on the ABB drive, possibly the fault was intermittent and coming on/off too fast for the CPU to detect it, but fast enough for the drive to react to it. What was the diagnostic message on the drive (I doubt the drive just decided to stop without placing an error code on the display)?

This type of undetected  fault is why you will often see in Profibus maintenance chapters for DP slaves a note such as "in case of error, please check/replace Profibus connectors and/or cables". It is a required but sometimes demanding task.

In any case, glad you could identify and correct the fault. Now you have a list of tests that will identify defective connectors, it should make your life easier.

Again, about your channel question: if you have this kind of channel fault, it may lead to intermittent, hard-to-diagnose faults...

Hope this helps,

Daniel Chartier