Siemens S7 Plus Ethernet | Symbol reloading takes too long

[BR_10657397]

Hi,

Is there a possibility to stop KepserverEx + Siemens S7 Plus Ethernet from loading symbols from the PLC every time a client connects ? This takes a very long time for every client connection and really is not needed for my use case (All necessary static tags where manually added).

I already disabled following settings on the PLC node:

- Tag Generation / On Device Startup = Do Not Generate on Startup

- Communications / On Invalid Tag = Disable

[rajskumar]

Hello,

Is this happening every time a new client connects to Kepware, even when there is already an existing client connection, or when the first client connects to Kepware (i.e., the number of clients switches from 0 to 1)?

[BR_10657397]

Hi,

Thanks for the reply, I did some tests with an additional client and the loading happens when client switches from 0 to 1, It does not happen when switching from 1 to 2 clients.

[rajskumar]

Thank you for the clarification.

This is expected behavior and cannot be prevented. When a client connects, driver load the symbol to determine the memory location of tags. Is there any specific reason your client connects and disconnects repeatedly? Typically, the client should maintain the connection.

As a workaround, you can keep Quick Client running with only one tag being read, so it won't load the symbol again when your actual client connects.

[BR_10657397]

The client generally stays connected, but the delay is very noticeable (around 20 minutes) the times i need to restart the client or the host.
Admittedly there are way more PLC tags set to accessible then needed (at this time) so I will definitely work on that. It's a pity the driver wants to load all the symbols even though I only need a very small subset which are even configured as static tags.

[rajskumar]

I understand your concern, but we only have the tag name(static tags). When a client connects, it needs to load the tag locations, so it will reload whenever a client connects for the first time.

Also You are right, only necessary tags should be in the project to keep it optimized. Below is the article that can help optimize the project.

CS292754 - Configuration project performance optimization in PTC Kepware Products

[BR_10657397]

Thanks for the article, 
In TIA I have considerably brought down the number of tags 'visible to OPC'  to a few thousand tags, there is however still the same large loading delay, So going further i will first look into the CPU load for communication taks and if there are other bandwidth limitations.

[rajskumar]

Please let us know your findings.

If the issue persist, I recommend opening a support ticket with the Kepware Technical Support team. Here is a link to the My Kepware login page where a ticket can be submitted:

https://my.kepware.com/s/login/

[BR_10657397]

Ronny,

ter info

Met vriendelijke groeten, Salutations distinguées, Kind Regards,

Bart Reyntjens
Automation Engineering Architect
T +32 56 434526 • M +32 485 525071 • bart.reyntjens@tvh.com

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