RJ45 straight through or crossover?

[TL140]

Hi all!

So I am still having issues communicating with some controllers at the plant through the ethernet/ip drivers. We are using 1769-L32E compact logix connected to a stratix 5700.

I know absolutely nothing about the stratix switch. However I did notice that the PLC is connected to the switch with a straight though cable. I have been connecting to the programming port on the side of the machine with a straight through. The jumper from the port to the stratix is also straight through. Will I need a crossover to communicate properly? Or is the issue more that my LAN settings and RSLinx are not configured properly?

 

[rdrast]

Use all straight through patch cables. The only time you might need a crossover is if you are connecting two older end-node devices (like a PC or PLC) together without auto MDI-X ports.

The most likely cause of Ethernet comms problems are incompatible network addressing/settings or bad cabling. I propose the electro-shock therapy for anybody that crimps on a male 8P8C plug on any Ethernet cable.

 

[TL140]

Hmm, Alright. Might you have a guide of setting up the ethernet/ip communication to a pre configured controller then? I've scoured google and have looked through so many guides and manuals and tried so many things with little results.

The only info that I have is the subnet address of the controller, the IP address of the controller, and the gateway for it. I have tried configuring my LAN network settings and also configuring the ethernet/ip driver with every possible configuration that i could think of. Still no luck! Tried connecting through the stratix, directly to the controller, and even tried swapping cables. I am on night shift and we have no engineers here or on standby and no one has gotten back with me on any way to solve this issue. The machines are about 6 months old and we have a semi-annual PM to backup the programs that my boss put me tasked with

 

[OdinIII]

I propose the electro-shock therapy for anybody that crimps on a male 8P8C plug on any Ethernet cable.

May I ask why? We've never had a problem with those... yet?

 

[mk42]

One other thing you might want to look at is whether the ports on each device and switche are set to auto-negotiate the speed, or set for 100 duplex.

Some sources will tell you different things about whether auto-negotiate or specifying 100 duplex is better (I prefer autonegotiate), but the really important thing is to make sure both sides of each ethernet cable have the same setting. If one side is set to auto-negotiate and the other is fixed, then they both fall back to 10 half duplex, which is problematic and can cause all kinds of hard to troubleshoot problems in the network.

 

[rdrast]

May I ask why? We've never had a problem with those... yet?

They are prone to failure. 95% of installations with that **** use solid wire, which inevitably breaks off after crimping and flexing a bit, causing intermittent ghostly communications failures. The other 5% use stranded wire, which is better, but then they don't use the proper crimp 8P8C connectors for stranded wire (they are different from solid). Or, and installer uses whatever 8P8C connector they happen to find in a bulk pack, and the wrong crimp tool; While plug-compatible, 8P8C WE/SS connectors wont crimp properly with a Tyco/Amp tool, and vice-versa.

Using a regular punch down tool, and an 8P8C jack, then standard pre-made patch cords is much more reliable, and often results in a neater installation to boot.

 

[TConnolly]

Instead of a punch down block, use these. It din rail mounts and you don't need any special tools.



That said, I crimp ends all the time - never have a problem.

 

[willxfmr]

The first thing I would check is that the IP address of the controller is listed in RSLinx. If it is, then I would make sure the IP address of my computer is compatible. For example, if the IP address of the controller is 192.168.10.10, with a subnet mask of 255.255.0.0, then the IP address of my computer will also need an IP address that starts with 192.168.xxx.xxx, and have a subnet mask of 255.255.0.0. At that point the only issue would to to make sure you don't have the computer IP address set the same as any other device on the network. If the switch sees 2 identical IP address from different pieces of hardware, it will simply ignore both those devices. As long as RSlinx hap the right IP address to look for and the computer is set correctly, connecting should not be a problem. Hope that helps.

Will.

 

[Paullys50]

Err...it could be the Stratix

Early versions of firmware for the Stratix 5700 were ****...we went through alot of hassle when RA supplied a Centerline MCC for a project loaded with the 5700. Had similar issues, had to swap to cross-over cables even though the setttings in the 5700 were correct to all the use of either.

Anyway I would check the firmware revision you have, find the latest firmware and update it. Read the release notes to see if it lists the issues you are seeing.

The "should" be ok now. But hey...Rockwell.

 

[RussB]

A long time ago I had a PCMCIA Ethernet card that someone fried for me (that's another story) I put a RJ-45 connector on the end that used to plug into the PCMCIA card and made 4" long Crossover 'adaptor' to carry. It is now in my 'extra' cables file under 'Miscellaneous'.

 

[harryting]

Everyone should carry a cable tester as part of their kit. I also seen a lot of badly crimped RJ45 plug but sometime termination is unavoidable in which case I use the EZ-RJ45 set from Platinum Tools.

 

[TL140]

Thanks for the feedback guys. I am not quite allowed to change firmware on the switch as I am just a maintenance tech. I will definitely have to email a control engineer about that. Wish I could get more assistance, however being on nightshift, my resources are very limited.

As for the IP address, I have configured my LAN with the same subnet mask and the same 192.168.0xx.xxx. does it need to be the same number on the third number? anyways I still do not get any reading of any controller on RSLinx. Still using straight through cables as suggested, and havent been able to get a crossover. We only have one cable and it is a straight through and I really dont wanna make modifications to it and mess it up. IT may have one, but as i said before...

Nightshift

 

[Freak]

The IP address should be different for the third number. There have been some excellent descriptions on what all of the numbers mean on this forum.

Do you get any flashing lights when you are plugging in? You should see a light on the port you plug into as well as the port on the laptop, no light would suggest no communication.
Also Stratix switches take a long time (several minutes) prior to allowing communication on the port.

 

[rdrast]

What exactly are your network addresses (the actual Address part, 192.168.1.42 for example), your actual Subnet Masks (255.255.255.0 in decimal or 192.168.1.0/24 in CIDR notation for example), and whatever gateway addresses you have set on all devices.

 

[TL140]

The controller I have has an IP of 192.168.18.73. The subnet mask of it is 255.255.252.0. The default gateway is 192.168.16.1, and the DNS is 10.209.8.51.

Thats the information in our log book with the schematics. And that is for all of our controllers, with the last digits in the IP changed. I can connect to the rest just fine because they have a network adapter. This one however, does not.