IP Addressing and Control Logix

[gizmo]

Here's what I got:
A 17 slot control logix rack with 2 - 1756-ENBT modules.
One ENBT module(information hwy)(I/P=170.166.99.100) communicates with a PC running Wonderware, PC running RSL5000 along with the mill's main ethernet network.

The other ENBT module (control hwy) (I/P=10.10.10.10) communicates with a couple of FlexLogix remote racks via a 1794-AENT module (I/P=10.10.10.11 & 10.10.10.12 & 10.10.10.13).

Note: All subnets are 255.255.255.0

When I run RSLinx, I expand the following tree:
-Workstation(170.166.99.200)
----AB_ETH-1,Ethernet
--------1756-ENBT(170.166.99.100) (1st ENBT module)
------------ControlLogix BackPlane
---------------1756-ENBT(10.10.10.10) (2nd ENBT module)
-------------------AB_ETH-1,Ethernet
-----------------------????

Question #1:
I was expecting to view the 10.10.10.xx flex AENT modules where the ???? are above. Why can't I see them?


Question #2:
I'm going to add a PanelView 600(ethernet) to this system. My question is should I add the PanelView 600 to the Info Hwy and give it a "real" IP Addr or the Control Hwy and give it a 10.10.10.xx IP Addr. If I add it to the Conrtrol Hwy, will I be able to download to it from the Configuration PC (170.166.99.200).


Thanks!

[kamenges]

We had an issue like this recently after one of our engineers installed RSLinx. One of the options for the install has to do with installing all the EDS files. It appears (and someone correct me if I'm wrong) that Linx needs the EDS files to determine what device it sees out on the various networks.
In our case the IP addresses showed up but they had the question mark symbol over them and we couldn't burrow into them.
We had the latest version of Linx so we did a full-blown Linx install and everything was cool. You may need to upgrade your version of Linx or at the least get all the latest EDS files to see what you want (assuming I'm right about the EDS file thing).

As for the HMI I would personally add it to the info highway. My reasoning is pretty esoteric but I don't like the idea of the HMI using up control bandwidth. Granted, Ethernet is pretty fast and the HMI loading will be light. It's just a personal preference. In terms of downloads I think you will be OK either way.

Keith

[Ken Roach]

I think what's going on is that the RSLinx driver doesn't know how to "browse" a remote IP network.

When RSLinx tunnels through a Logix system to get to DH+ or ControlNet or DeviceNet, it has a fixed number of addresses it can browse; 63 for DH+ and DeviceNet, and 99 for ControlNet.

For an IP network though, there can be as few as 254 addresses (on a Class C network) or as many as billions (consider the Internet !). Therefore the RSLinx designers just punted on the question; the regular AB_ETH driver does not "browse" per se.

Instead, when you set up the "AB_ETH" driver, must you configure a Station = IP equivalency list, and you can't browse IP addresses that aren't in that list. I don't know if adding the 10.10.10.x addresses to that list will make a difference in your case, but it's painless to try it.

I know that the new "EtherNet/IP" driver in RSLinx 2.40 is supposed to allow RSLinx to browse Class C IP subnets. But I don't know if that extends to networks you have accessed through a Logix backplane. So far I haven't been able to get the new EtherNet/IP driver to discover any of my 1756-ENET/B modules, though have beeen told it will discover 1794-AENT, 1756-ENBT, and 1788-ENBT. I just got a couple of my Logix demos back from the field and I'll plug some in this afternoon and see what happens.

Darn Good Question, gizmo !

[gizmo]

I've already tried adding the 10.10.10.x to the "Configure Driver" List under "AB_ETH". It comes back with a " ? Unrecongized Device ". I (so far) haven't had any problems with RSLinx 2.30 recognizing our 1794-AENT, 1756ENBT/B, PanelView600 or 1761-NET-ENI modules with Class C IP address. The problem is with the 10.10.10.x addressing of devices off the ENBT through the CL backplane.

The remote Flex rack with the 1794-AENT (10.10.10.11) does communicate with the CL processor. We're testing it right now. Everything seems to be working/communicating. Just curious why I couldn't see the 1794-AENT with RSLinx. Also if I added a PanelView with a 10.10.10.x address to the system would I be able to download/upload to the terminal. How could i set my path if RSLinx doesn't show the 10.10.10.x devices.

If that makes any sense, I'm starting to get confused.
Thanks for all the Help!

[Gerry]

I'm no expert on this subject and would like to hear the end solution. However, I think the problem may be the different sub-nets. Note that 255.255.255.0 is the sub-net MASK and the sub-nets being used are 10.10.10 and 170.166.99
I know that two devices with the same sub-net mask but with IP addresses that specify different sub-nets can't communicate directly.
Perhaps if you try setting up the Flex IO network with a sub-net of 170.166.98 and change the mask to 255.255.254.0 in your RSLinx station...? (254 would pass 98 or 99)
If I had enough hardware I'd try this myself...

[Ken Roach]

I think I figured it out... to my surprise there is a new "browse a remote IP subnet" feature in RSLinx 2.40.01.

Navigate across the Logix backplane to the 1756-ENBT on the I/O network and to the Ethernet port on that network. Right-click, select Properties, and you'll see a Browse Addresses tab. This tab allows you to enter a list of IP addresses to browse on the remote Ethernet subnet.

I entered the address of the remote 1794-AENT, and viola !

[attachment]

This ought to allow you to download to your EtherNet/IP PanelView as well.. let us know !

[gizmo]

It looks as if you might be on to something. I won't be able to try it out until tuesday next week. I sure appreciate you taking time out of your day to setup and test this problem.
I'll have to see if my RSLinx Ver. 2.30 has this feature.

Thanks Again,
I Love This Site!

[gizmo]

Thanks again Ken,
It appears that my RSLinx 2.30.00 does support "browse a remote IP subnet" feature.
I'm back in business!