Ethernet. Whats gone wrong

Hi, I have an ethernet network connecting together 5 control logix processors. I can plug in to any hub and go on line. I used to be able to unwrap a length of cat 5 cable (40 metres) and plug in and work at a distance from the hubs. Not anymore. The windows icon says the cable is unplugged and RSLinx returns a comm error of 01E00204.
The cable tests OK. (Have tried several cables)
The hubs used are netgear 4/5 port. All cables at the hubs are into the normal holes, ie none are set for uplink. Distance between hubs is approx 70 metres. This one has me beat.
Also I am trying to set up a wireless access point (Belkin) to allow me to go online anywhere on the floor with my notebook. Any one had success with this.
Regards Alan

Answering my own question.
All the experts at this site (where I am working at present) told me the pairs did not matter as long as they were the same both ends.

Copy from another source.

Ok if your connection light between the switch/hub and the computer is off than the cable is wrong. For this connection, hold the connector with the copper side up and the opening toward you pin 1 is on the left pin 8 to the right, pin 1 orange, 2 or/wh, 3gr, 4 bl/wh, 5 bl, 6 gr/wh, 7 br, 8 br/wh. On the other end you do the same thing and your cable should work.

You can swap the pair colors as long you keep a pair for pin 1 + 2 and a pair for pin 3 + 6 because the data is transported thru these pairs. On the hub if you have a uplink port use the same cable as above, plug it into the uplink port on one of the hubs and use a regular port on the other one. If there are no uplink ports then you need a crossover cable connector pin 1 + 2 to connector 2 pin 3 + 6 and visa versa.

Hope this helps

Carel Colpa
CESystems
[email protected]

Ethernet problem

Have you tried to ping the ethernet cards in the PLC rack? Do this in a Windows command window (type "ping /?" for help). Are you sure the laptop computer is on the same network as the PLC's (IP address)?

I have a customer that is using the wireless ethernet connection to go online to their PLC's within a plant, their connection is very slow (1/3 the speed of hardwire) but that may be the hardware they used.

Some more slightly conflicting info

http://yoda.uvi.edu/InfoTech/rj45.htm

The notebook is setup correctly as I can go online with a short patch cable, my homemade cables though they were pin 1 to pin 1 etc need to have the pairs matched as per the info in the links.
Regards Alan

Alan,

the info you posted in your last thread is the way I have always wired and seen cables wired. Take a look at any of the cables you have there that are store bought and I bet they match that webpage. But as you stated earlier it shouldn't matter as long as both ends match. I have a $50 tester that I use on any cables I make, saves time trying to debug stuff when it is just a bad cable. If the only difference between it working and not working is your use of your hand built and store bought cable I'm willing to bet the problem is your cable.

I use 802.11b all the time to connect to my PLC's in our plant. Best thing since sliced bread in my opinion. Make sure you have the correct cable plugging the wireless hub into the regular hubs. Most likely you will need to use a cross over cable. If you haven't set up a wireless network before I recommend having all the security settings turned off until your sure your getting a link. WEP and other security settings can make it look like it's not working when in fact you just don't have the security settings correct.

But as you stated earlier it shouldn't matter as long as both ends match

Click to expand...

Just having the ends matching is mostly okay for digital telephone systems, and slow 10base-T systems, but anything at 100Base-T and above, it is absolutely critical to keep the pairs together.

For 4 twisted pair cables, the two 'standards' are T568-A and T568-B.
Why? beats me. Probably so someone could tell by looking at a connector what 'should' be connected to it. /shrug.

568-A is generally for analog type signals, including most RJ45 wired PBX phone systems, even though the actual transmission is digital.

568-B is used for dedicated data transmission, mainly twisted-pair ethernet.

In both standards the same pairing is used. The actual pairing is:
pins 1/2, pins 4/5, pins 3/6, and pins 7/8. Numbering and color conventions change between 568-A and B though. In 568-A (analog) the following standard is used:

Pair Pins Base color
1 4 & 5 Blue-Blue/White
2 3 & 6 Orange-Orange/White
3 1 & 2 Green-Green/White
4 7 & 8 Brown-Brown/White

In 568-B (Data) the following standard is used:

Pair Pins Base
1 4 & 5 Blue-Blue/White
2 1 & 2 Orange-Orange/White
3 3 & 6 Green-Green/White
4 7 & 8 Brown-Brown/White

Pairs 1 and 2 in either are the PRIMARY pairs, with pair 1 actually being the old 'Tip and Ring' from RJ11 phones. (which is why if there is an analog phone system, but wired RJ45, you can plug an RJ11 phone in and it will work, but that's trivia).

Anyway, point is, the pairs need to match, as the cables are designed to minimize crosstalk between pairs. For Cat5 and above cables, even when terminating, there should be a twist within 1/2 inch of the actual termination point.

And even a cheap cable tester can save weeks of frustrating troubleshooting

Every time I've had problems with ethernet, it almost always wound up being a cable problem. I have had plenty of 'factory-made' cables that give intermittent problems, so don't assume that a 'new' cable rules out a cable problem! Also, when making your own cables, it pays to use a good quailty crimping tool... :nodi:

For future reference, HERE'S a very good set of cable wiring pictures...

beerchug

-Eric

Good success with wireless access

I have had excellent success with the Orinoco wireless access to my PLC's. I can pick up a good signal at 10 Mbs over 300 feet away (inside a plant filled with metal obstructions). And I can pick up a useable signal over 600 feet away!!

And I have even picked up a good signal over 100 feet away with the access point closed up inside the electrical panel. I always use this approach when starting up a new line... saves time and steps.

Sorry to bump this post, but I'm having the same error code in 2019. I'm able to ping it, also another computer on the same network is connected to this PLC. But I'm not able to add it to RSLinx without this error.

Please help!

-PreLC


Update: My IP Address had an extra '.' in it, rendering it useless. Thanks for the help!

Alan Case said:

Also I am trying to set up a wireless access point (Belkin) to allow me to go online anywhere on the floor with my notebook. Any one had success with this.

Click to expand...

Yes, I've used a Belkin WAP to connect to a process network. It was very simple and straightforward, but that particular network employed only fixed IP addresses.

PreLC said:

Sorry to bump this post, but I'm having the same error code in 2019. I'm able to ping it, also another computer on the same network is connected to this PLC. But I'm not able to add it to RSLinx without this error.

Please help!

-PreLC


Update: My IP Address had an extra '.' in it, rendering it useless. Thanks for the help!

Click to expand...

I have encountered a situation in which I could ping CLX PLCs on a network but couldn't communicate with them. It turned out to be a failed Ethernet switch.

EDIT: Glad to hear that you found your problem.