Help! SLC505-rslinx-ethernet problem

[Ken Roach]

Since you can use the OPC Test Client to connect and communicate with the SLC controllers even in a "lockup" situation, you have proven that RSLinx Gateway is accepting new OPC requests, and that the SLC controllers are available to communicate with RSLinx.

It's unlikely that you are running out of TCP connections to the controllers; even the smallest and oldest 1747-L551 version of the SLC-5/05 supports 16 TCP connections. Besides, RSLinx Gateway is only going to use one TCP connection to the SLC, no matter how many requests are being made over OPC.

 

[kamenges]

I guess my next step would be to put an OPC client on the production line computers (other than the VB client already there) and try to do an OPC request across the network. Take a look here if you need a test client:

http://www.opcconnect.com/freecli.php

If you can make successful OPC requests with that it is something specific about the VB OPC calls or the ERP triggers.

Keith

 

[Ken Roach]

It sounds like the OPC Test Client is on the same computer as the RSLinx Gateway software, so its connection is over a local OPC link.

I'd test by attempting to run the OPC Test Client on a remote machine, to be sure that RSLinx Gateway is still accepting Remote OPC connections.

Another examination to eliminate network problems as suspects is to browse the SLC-5/05 with an internet browser. The embedded web page contains a good deal of information about how many devices have current TCP connections with the SLC, and about how many packets per second it is serving up to other clients.

[Edit: Keith and I are thinking along the same lines]

 

[JOHN F NASH]

Hi ALL
The problem is Just the third part soft resolve the ERP send's command and sended OPC Request,OPC protocol I understand and I use my owner designed soft opc client to communication with some OPCSERVER eg WinccOPCServer...,when you request data from server just by COM technology only.and you should appoint items which you need items data

Good luck!

 

[Ken Roach]

As you have seen, there are a lot of diagnostic tools available to you in the DDE/OPC menu of RSLinx.

If I were in your seat I'd be comparing the normal running values to the values during a "OPC lockup" in the Active Topics list, and the Server Diagnostics statistics table, in the OPC Group Diagnostics table, in the Optimized Packets list, in the DDE/OPC Communications Event Log... pretty much everything under the DDE/OPC menu. Maybe you can lean on the "refresh" button and see the events happen when an ERP application executes one of its transactions.

Your description of the VB application makes me think that it opens an OPC topic, runs a transaction, and closes the topic every time it executes. Most OPC clients connect to the OPC server and then spend their days and nights continuously
exchanging data with the OPC Server over that connection.

If I had to guess about a system that could cause an overflow in opened/closed connections, it would be one like this.

 

[Ken Roach]

Just reading through the Knowledgebase on this sort of thing.... do you know if the DCOM properties are set to run RSLinx under a System account or under a User account ? If it's running as a user account you can get multiple instances of RSLinx that fire up (they're visible in the Processes tab of the Windows Task Manager) and will choke off the Remote OPC Server without generating an error in the error logs (Knowledgebase #28638).

 

[JOHN F NASH]

Ken Roach
Your description of the VB application makes me think that it opens an OPC topic, runs a transaction, and closes the topic every time it executes. Most OPC clients connect to the OPC server and then spend their days and nights continuously
exchanging data with the OPC Server over that connection.

perfect

when you communication with the third part you should not activate connect OPCServer and then disconnect soon,you should keep the connect resource.and then next time you could request data from Server direct!

 

[hatchor]

Thanks for all the thoughts and suggestions. The VB application runs, waits and then closes, and as far as I know it does not keep an open connection..... but Ken's suggestion of opening and closing all the time causing an overflow makes sense, and is backed up by John.

Ken, in response to the DCOM settings, under RSLinx Properties, identity, it is set for the interactive user. I cannot use the system user because the third party VB app will not work when RSlinx runs as a service. We need to run it in application mode only. Sorry, I should have specified this earlier.

 

[JOHN F NASH]

contact with the third part,and you could real known where the problem occur and why,because the communication's node is not just direct but have the third parts.

Good luck!

 

[hatchor]

How can I browse to the embedded web page of my SLC5/05 as suggested below??

"Another examination to eliminate network problems as suspects is to browse the SLC-5/05 with an internet browser. The embedded web page contains a good deal of information about how many devices have current TCP connections with the SLC, and about how many packets per second it is serving up to other clients."

 

[Freak]

Get on the PLC network, open Internet Expolerer and type in the IP number.

Peter

 

[hatchor]

Get on the PLC network, open Internet Expolerer and type in the IP number.

Peter

haha, sorry, I was connected to a different VLAN and wondered why I couldn't connect!! Duh...
Thanks Pete

 

[TWS]

The network is a mixture, but the managed switches are autosensing for speed and all the network is connected to a Cisco router. Thanks,

The ports on your switches switches conected to the PLCs should not be set for autosensing.
See page 12 of: http://literature.rockwellautomation.com/idc/groups/literature/documents/ap/enet-ap001_-en-p.pdf

 

[1_1_1]

it does sound like an issue with the 3rd

btw a temp fix until it can be properly fixed is set a scheduled task of "shutdown.exe -r -t 00" to run daily this will reboot the computer

the shutdown.exe program is in XP but not 2k however it can be copied to 2k

if you want more info on the command then open a command prompt and type "shutdown /?"

also check for memory hogs (task mamager>proformance) and set the computer to best proformance (right click on "my computer">properties>advanced>proformance settings>)
I do this on all work computers as it lowers the memory load a little

 

[1_1_1]

The ports on your switches switches conected to the PLCs should not be set for autosensing.
See page 12 of: http://literature.rockwellautomation.com/idc/groups/literature/documents/ap/enet-ap001_-en-p.pdf

you can have issues with some switches but I've had the cisco 2960 thats used at work for the plc network set to auto and the plc's set to force 100 (if possible) and it works fine