Line Noise in a Network

[gar3555]

Are there any tools, that can be used to check for line noise in a LAN. At my work, we have a contract with a company, and they are having problems with their lines, they have blamed us for our 3-D software we put in, but we think it is the lines themselves, they run along in unshielded cable next to huge DC motors and VFDs. Since we added this new software, the traffice has increased, and with this increase the EM effect of the motors has increased, and resulted in data loss. We need to prove this, so that is why I'm asking, any network people know of anything that can check for this?

 

[Googer]

You could measure it with an oscilloscope.

 

[spidey07]

any errors on the LAN ports could be an indicator of trouble. A 100/full lan link should have zero errors.

But in reality it takes a tremendous amount of EM to cause problems - I've installed huge networks for GM/Toyota in their plants...talk about heavy machinery without issue.

You could have a cabling expert come by and make sure the cable is within specification. I believe the minimum distance from high power eletrical lines is 4 feet.

Another possiblity is the cabling plant isn't all that good or was installed improperly meaning that it is VERY affected by any EM.

-edit- what to look for is CRC or FCS errors/counters on the lan switch port. each frame has a checksum (CRC) and that verifies the frame is intact.

 

[gar3555]

Originally posted by: spidey07
any errors on the LAN ports could be an indicator of trouble. A 100/full lan link should have zero errors.

But in reality it takes a tremendous amount of EM to cause problems - I've installed huge networks for GM/Toyota in their plants...talk about heavy machinery without issue.

You could have a cabling expert come by and make sure the cable is within specification. I believe the minimum distance from high power eletrical lines is 4 feet.

Another possiblity is the cabling plant isn't all that good or was installed improperly meaning that it is VERY affected by any EM.

-edit- what to look for is CRC or FCS errors/counters on the lan switch port. each frame has a checksum (CRC) and that verifies the frame is intact.

another problem is that they are using UTP cable, without conduit which is a huge concern. And also makes our point even more likely. Also this is for a big assembly line that performs plastic extrusion.

 

[spidey07]

well if it is a couple feet away it shouldn't matter.

if it was installed properly

but I'm a little confused...whose blaming whom for what?

 

[gar3555]

Not really blaming, they just want there lines to work, and they don't know what the problem is, but they reason that since it started failing 6 mo after we added our part, that it has something to do with that.

Also, I haven't been onsite yet, I'm going Wednesday, but this is what the other engineer who has been down there is telling me...I'll know the whole enchilada then

 

[spidey07]

I'd scan the ones having problems and see if they meet CAT5 spec. Its normally the biggest problem with networks - poor cabling. And the symptoms it can cause are quite infuriating/confusing.

 

[gar3555]

cool, I'll have to mention that, we're headin down there wednesday...4 1/2 hr drive, have to leave work around 2:30 am, gonna be a long rest of the week.

 

[spidey07]

gotcha...

this statement comes from serious experience:

"if you are troubleshooting a physical layer problem (and it sounds like you are) you will never be sucessful without a full-fledged CAT5/5e/6 scanner" They are worth their weight in gold even at a few thousand dollars a pop.

IMHO absolutely a required device for networks. Can't run one without them and it must be one that will certify the cable and nothing less.

 

[gar3555]

Originally posted by: spidey07
gotcha...

this statement comes from serious experience:

"if you are troubleshooting a physical layer problem (and it sounds like you are) you will never be sucessful without a full-fledged CAT5/5e/6 scanner" They are worth their weight in gold even at a few thousand dollars a pop.

IMHO absolutely a required device for networks. Can't run one without them and it must be one that will certify the cable and nothing less.

Who makes em, does AB or Fluke? cuz we can get ahold of one very easily if they do. As we also need to troubleshoot the DeviceNet and ControlNet areas as well?

 

[spidey07]

Originally posted by: gar3555

Originally posted by: spidey07
gotcha...

this statement comes from serious experience:

"if you are troubleshooting a physical layer problem (and it sounds like you are) you will never be sucessful without a full-fledged CAT5/5e/6 scanner" They are worth their weight in gold even at a few thousand dollars a pop.

IMHO absolutely a required device for networks. Can't run one without them and it must be one that will certify the cable and nothing less.

Who makes em, does AB or Fluke? cuz we can get ahold of one very easily if they do. As we also need to troubleshoot the DeviceNet and ControlNet areas as well?

fluke makes great scanners (they bought omni-scanner)

I guess I cannot stress enough how invalubale these are. At a few thousand bucks a pop it sounds like a lot, but paying a tech to troubleshoot a problem is way worse.

Would you expect an electrian to fix a problem without a fluke/meter? no, and neither would I expect a net tech to fix one without a fluke scanner.

http://www.flukenetworks.com/us/Cabling...abling/DTX+Cable+Analyzer/Overview.htm

 

[gar3555]

Originally posted by: spidey07

Originally posted by: gar3555

Originally posted by: spidey07
gotcha...

this statement comes from serious experience:

"if you are troubleshooting a physical layer problem (and it sounds like you are) you will never be sucessful without a full-fledged CAT5/5e/6 scanner" They are worth their weight in gold even at a few thousand dollars a pop.

IMHO absolutely a required device for networks. Can't run one without them and it must be one that will certify the cable and nothing less.

Who makes em, does AB or Fluke? cuz we can get ahold of one very easily if they do. As we also need to troubleshoot the DeviceNet and ControlNet areas as well?

fluke makes great scanners (they bought omni-scanner)

I guess I cannot stress enough how invalubale these are. At a few thousand bucks a pop it sounds like a lot, but paying a tech to troubleshoot a problem is way worse.

Would you expect an electrian to fix a problem without a fluke/meter? no, and neither would I expect a net tech to fix one without a fluke scanner.

http://www.flukenetworks.com/us/Cabling...abling/DTX+Cable+Analyzer/Overview.htm

sweet, thx, I'll tell the boss first thing in the morning...see if we can't get our hands on one of those

 

[spidey07]

If only to repeat myself (mainly for others who may be reading)

This is required for maintaining a network. It is not optional. It is required equipment. It is mandatory, not optional.

 

[gar3555]

I'm surprised our company doesn't have one of these already, all our automation is going away from DH+, and heading to ethernet, if it isn't already there...except of course for GM and Ford, they are stubborn about changing... btw DH+ sucks

 

[spidey07]

don't know what DH+ is...

but I've been in the manufacturing world for a while. Without wired and wireless network coverage for every square foot of the floor you are waly behind.

EVERYTHING is ethernet now. From the little robots that get their instructions/orders via wireless to the PLCs that are always reporting/monitos ring - if it ain't talking its worthless.

 

[gar3555]

Originally posted by: spidey07
don't know what DH+ is...

but I've been in the manufacturing world for a while. Without wired and wireless network coverage for every square foot of the floor you are waly behind.

EVERYTHING is ethernet now. From the little robots that get their instructions/orders via wireless to the PLCs that are always reporting/monitos ring - if it ain't talking its worthless.

It's Data Highway Plus, a very outdated network comm

 

[spidey07]

Originally posted by: gar3555

Originally posted by: spidey07
don't know what DH+ is...

but I've been in the manufacturing world for a while. Without wired and wireless network coverage for every square foot of the floor you are waly behind.

EVERYTHING is ethernet now. From the little robots that get their instructions/orders via wireless to the PLCs that are always reporting/monitos ring - if it ain't talking its worthless.

It's Data Highway Plus, a very outdated network comm

heh, there's this new fangled thing called "internet protocol".

Its all the rage being as how new it is (circa 1970)
😉

 

[gar3555]

Originally posted by: spidey07

Originally posted by: gar3555

Originally posted by: spidey07
don't know what DH+ is...

but I've been in the manufacturing world for a while. Without wired and wireless network coverage for every square foot of the floor you are waly behind.

EVERYTHING is ethernet now. From the little robots that get their instructions/orders via wireless to the PLCs that are always reporting/monitos ring - if it ain't talking its worthless.

It's Data Highway Plus, a very outdated network comm

heh, there's this new fangled thing called "internet protocol".

Its all the rage being as how new it is (circa 1970)
😉

yeah, but PLC5's don't like ethernet 🙂

 

[Googer]

Originally posted by: gar3555

Originally posted by: spidey07
gotcha...

this statement comes from serious experience:

"if you are troubleshooting a physical layer problem (and it sounds like you are) you will never be sucessful without a full-fledged CAT5/5e/6 scanner" They are worth their weight in gold even at a few thousand dollars a pop.

IMHO absolutely a required device for networks. Can't run one without them and it must be one that will certify the cable and nothing less.

Who makes em, does AB or Fluke? cuz we can get ahold of one very easily if they do. As we also need to troubleshoot the DeviceNet and ControlNet areas as well?

FLUKE