RSLogix 5000 - Failed to go online with the controller. No open connection

[JingPolz 0]

Hello everyone Its so nice to be here! I have a problem. I am getting this error message "Failed to go online with the controller. No open connection." everytime I connect to any of the 11 Control logix controllers in our network thru DH+. I tried to connect using 4 other different workstations but still I am getting same error. Note that these 11 CLX controllers are using msg write to the 12th CLX controller, thru DH+. I dont have problem connecting with the 12th CLX controller though using ethernet connection. Any help would be appreciated. Thanks so much. Jing Edited 28 Jun 2007 by JingPolz

[BobLfoot 301]

Let me restate your situation to make sure I have it right. CLGX 1 connects DH+ to CLGX 12 CLGX 2 connects DH+ to CLGX 12 CLGX 3 connects DH+ to CLGX 12 CLGX 4 connects DH+ to CLGX 12 CLGX 5 connects DH+ to CLGX 12 CLGX 6 connects DH+ to CLGX 12 CLGX 7 connects DH+ to CLGX 12 CLGX 8 connects DH+ to CLGX 12 CLGX 9 connects DH+ to CLGX 12 CLGX 10 connects DH+ to CLGX 12 CLGX 11 connects DH+ to CLGX 12 Workstation 1 connects or can connect to CLGX 12 via ethernet Workstation 2 connects or can connect to CLGX 12 via ethernet Workstation 3 connects or can connect to CLGX 12 via ethernet Workstation 4 connects or can connect to CLGX 12 via ethernet No workstation can connect to CLGX 1 thru CLGX 11 when you browse to CLGX 12 and thru the DH+ to that CLGX. If you have only one MSG from each CLGX and one MSG to each CLGX this is using at least 22 connections of the 1756-DHRIO card. Most likely you have exceeded the connection count. Try this - unplug a couple of CLGX from the DH+ and see if your problem disappears. More expert CLGX persons than me can give you exact data on this problem.

[JingPolz 0]

You understood my situation correctly. I already pulled out 5 DH+ nodes. But same message is coming up. But yeah I really believe this is something to do with the number of connections happening at the same time. Anyway, we have decided to place ethernet modules to each of the CLXs and see if this will help the problem. Doing the messaging thru ENET instead of DH+. I thank you so much for your help I really apprecaite it!!!