CIP connection error, panelview plus 600 compact

Hello you all people,
I am having a situation I can't understand, if anybody could please explain it to me it would be great.

Whenever I download an application to any of 8 panelview plus 600 compact and then try to modify any value from the panel program (writing to a tag in the PLC) I get the following error message in the panel:

Problem writing value 'x' to item '[PLC name]TAGNAME....
Write operation failed for item TAGNAME because write...
CIP connection (8000) open rejected (Error 11a0101) on route Com.....

Solution: restart the PLC and then everything works OK.
But I don't know why. This just happens when I make a modificatin in the panel program and download it.

Network: Ethernet/IP
Compactlogix L35E
8 flexlogic remote stations
8 panelview plus 600 compact
some ethernet switches.

I am downloading the application to the panel from my computer through the Ethernet network, should I download the application directly to the panel ? (disconnect it from the netowork, direct download to the panel, and reconnecting it to the network) ? or this has nothing to do ?

any comments appreciated.

This sounds like an ordinary TCP Connection Timeout issue. The PanelView's TCP connection isn't getting closed by the CompactLogix and so when the PanelView tries to open up a new connection, the CompactLogix rejects it.

The straightforward workaround is just to wait... after a few minutes the old connection will restart.

This issue is described in RA Knowledgebase Article (Access: Everyone) number 47538.

The rule of thumb I always used for PanelView Plus terminals is not more than 5 per ControlLogix or CompactLogix. Since the CompactLogix 1769-L35E only supports 32 CIP Connections, your sixteen TCP peers could easily use up all the CIP connections of the controller, depending on which features you use. The FLEX I/O uses at least one connection for the Rack Optimized connection and could use one per Analog or Specialty module. And the PanelView can use up to 5 Connections each, depending on what features you use (Global Connections, Data Model, HMI Tag Database tag count, etc).

A capture of data between the PanelView and the CompactLogix with Wireshark would show you conclusively if the TCP Connection issue is at the heart of what you're seeing, but you definitely also need to be aware of the limitations of the CompactLogix small controller.