Rslinx Dde Problem

[wander_who 0]

Hi all, Hopefully someone can help with an ethernet RSLinx DDE comms error I have. The system: - 1 computer (PC) - 1 control panel containing: CompactLogix L32E, PanelView Plus 1250, industrial ethernet switch - 1 control panel containing: SLC-5/04, PanelView 1400e, 1769-NET-ENI/B Each of the PLCs is controlling a separate Kiln (large industrial oven for ceramics etc). The computer runs two VB HMI programs, one for each kiln. Controller to HMI (VB program & panelviews) is Ethernet. Industrial ethernet switch is Hirschmann Spider 5TX. Ethernet link between the two plc systems and the computer is via the customer's dedicated VLAN (using cisco 2950 switches) The problem: Both of the VB programs on the computer are crashing at the same time, quite often (every couple of hours), due a DDE error. RSLinx sort of crashes (stays running but menus/RSWho etc will not work). We are working on fixing up our VB code so that our programs do not crash, but I also need to address the actual loss of comms to the PLCs which is causing the DDE error. We have done similar installs in the past - ethernet/RSLinx/compactlogix/VB program, and also multiple VB programs on the same PC for multiple PLCs. But this is the first time we have used multiple PLCs with multiple VB programs, and communicatins via RSLinx. Before connecting both plc systems to the customers network, we ran just one VB program on a laptop connected directly to the switch in the L32E's control panel, and had no comms issues. I am worried it is something to do with the customer's network, although we made sure to use switches, VLAN, etc.. I have checked & rechecked the RSLinx config. I have tried increasing the polled message times, and/or making the polling times differenent for each PLC, as well as increasing the error timeouts. But still RSLinx losses comms with the PLS etc, and does not recover. Any ideas? Cheers, Andrew W

[TimWilborne 108]

At first glance it sounds like a problem with the physical network. What is the distance of the Ethernet and what type of cable are you using or are you using fiber?

[wander_who 0]

Hi TWC, I have a feeling it might be related to the physical network as well - had some VPN & config issues with this customer already. The type of ethernet cable is CAT5e & CAT6e. Inside the control panel the calbes are about 1.5m (from switch to the PLC & PanelView), and the cable runs from the customer's switch to each control panel are maybe 80-100m. I do not think that any of the runs are greater than 100m. The original design was fibre optic link between two industrial switches, due to the distance. But the compromise design we ended up with was as my previous post. The seperate kiln network VLAN uses all switches, but the customer's existing network has a lot of hubs. To set up the VLAN, two new Cisco 2950C switches were used, hooked up to spare fibre optic ports in their IDF's. They have already started to use spare ports on the 2950's for their network - I wonder if this is causing problems? Cheers, Andrew

[TimWilborne 108]

Are the Plant and Office networks separated? They should be with a router connecting them together but from what I am gathering they aren't. Plus if you have any noise I wouldn't trust regular Ethernet cable at that length What do you have to do to get RsLinx back working or does it just start working again after a minute? Edited 27 Feb 2006 by TWControls

[wander_who 0]

Thanks for the quick reply I'm not sure about their plant network & office network - I know they use terminals at their production / inspection lines, and I wouldn't be suprised if these are not seperate from their office network... Other than those, the only other networked equipment in the plant that (that I know of) are our kilns. This is set up as a VLAN network, no access to/from the main network. I need to double check the cable lengths, but I a fairly sure they are not longer than 80m. The customer's installer ran the cables in metal conduits (mostly). To get RSLinx working again, all I have to do is shut it down and start it back up again (or stop & then start the service - I've tried both ways) Andrew W

[Snerkel 0]

Sounds like the VLAN is failing or delaying the packets, you really need to convince the customer that they need to seperate the networks.

[wander_who 0]

I have asked the customer to do some monitoring from their network, hopefully this will turn up something. In some ways it would be easier to fix if it was a simple configuration problem, or RSLinx Thanks for the replies, I'll see how it goes Andrew W