Dear,

I have machine with 20 nodes and connected with profibus DP. The cable length is about less than 100 M. And I am using 3 repeaters with the length of profibus.

I face problem only with one node. While running the line one node signal/ noise ratio getting down 0.25 volts and machine trip due to data packet loss.

All other nodes are working and profibus cable is laying with power cable but other nodes are working only one node having problem.

During stop time of machine no signal loss only happening during line running. No voltage of power cable as well when machine is stop.

Is it cause of Power cable? If yes why other nodes are working if no please share with your valuable comments.

Hello,

you can post better info about that node, is alone in cabinet or other nodes are close to it in same cabinet? What distance is before/after that node to next nodes, or position of repeaters to this node? It looks to me like this node is alone in some cabinet and some interference across make that bad things. Give us better info about topology, speed of Profibus is also important here.

Hello,

Some years ago I had a very similar problem and after so many unsuccessful attempts we found a problem in the profibus connector, doing a proper wiring in that connector we solve all machine trip.

In that case a connector with insulation piercing device (like attached img) was wired removing insulation from A and B cable, after some year without problem mechanical vibrations caused an increase of contact resistence in the connector. 

pieces

While running the line one node signal/ noise ratio getting down 0.25 volts and machine trip due to data packet loss

I'm just curious : how do you measure node signal/noise ratio?? 

Best Regards

mindware

Hello,

Some years ago I had a very similar problem and after so many unsuccessful attempts we found a problem in the profibus connector, doing a proper wiring in that connector we solve all machine trip.

In that case a connector with insulation piercing device (like attached img) was wired removing insulation from A and B cable, after some year without problem mechanical vibrations caused an increase of contact resistence in the connector. 

 

pieces

While running the line one node signal/ noise ratio getting down 0.25 volts and machine trip due to data packet loss

I'm just curious : how do you measure node signal/noise ratio?? 

Best Regards

 Dear,

I already change the connector and make a good connection as well but same condiotn.

And Signal to noise ratio I measure with profibus tester. In the profibus tester we can measure the quality of signal and its noise ratio as well.

Duris_I

Hello,

you can post better info about that node, is alone in cabinet or other nodes are close to it in same cabinet? What distance is before/after that node to next nodes, or position of repeaters to this node? It looks to me like this node is alone in some cabinet and some interference across make that bad things. Give us better info about topology, speed of Profibus is also important here.

 Dear,

this cabit is separate from other node/cabint and the distance is about 15 meter from another cabinet but the repeater I install on the same cabinet of the effected node.

Speed of profibus is 1.5MBPS.

I also thinks there is some interference but how can I reduce it and fix this issue.

One most important thing is the profibus is connected thorugh SLIPRINGS with the effected NODE.

pieces

 

Duris_I

Hello,

you can post better info about that node, is alone in cabinet or other nodes are close to it in same cabinet? What distance is before/after that node to next nodes, or position of repeaters to this node? It looks to me like this node is alone in some cabinet and some interference across make that bad things. Give us better info about topology, speed of Profibus is also important here.

 Dear,

this cabit is separate from other node/cabint and the distance is about 15 meter from another cabinet but the repeater I install on the same cabinet of the effected node.

Speed of profibus is 1.5MBPS.

I also thinks there is some interference but how can I reduce it and fix this issue.

One most important thing is the profibus is connected thorugh SLIPRINGS with the effected NODE.

 Hello,

  You have already followed all the shields? Look chapter 3

 http://www.profibus.com/uploads/media/PROFIBUS_Planning_8012_V10_Aug09.pdf