TCP Communication Settings

PLCnext Engineer and the PLCnext Technology controller communicate via a TCP connection with TLS Handshake.

If the TCP communication connection between PLCnext Engineer and controller is slow (e.g., via VPN) due to a poor connection quality or low transmission rates or if there is a high data traffic (e.g., while many online/debug data are transmitted), there are several parameters in the 'Options' dialog allowing to increase the stability of the connection and to optimize the transfer speed when downloading the project to the controller. The parameters influence the behavior of PLCnext services.

Select 'Extras > Options' to open the 'Options' dialog.
In the 'Online > Communication Settings' category, increase the following parameter values stepwise and check the influence of the modification on your system communication.
- 'Timeout': If the TCP connection is repeatedly terminated because responses on requests (such as connect/read/write commands sent to the controller) are delayed (TLS handshake fails), you can increase this value to make the connection more stable and reliable thus increasing its availability.
  The higher the timeout value the more stable is the TCP connection. However, an actual connection termination is only detected later.
- 'Polling interval': Increase the polling interval to reduce the (background) traffic load between PLCnext Engineer and the controller. This background traffic includes, for example, the transfer of online values, polling of controller attributes, such as the controller state, FW errors, etc.
  The higher the interval value, the less data is transferred in the background.
  
  Note
  The update rate of online values in online worksheets is directly influenced by the set polling interval. The higher the value, the longer the time until the next value update.
In the 'Online > Download Settings' category, disable the 'Use optimization' checkbox if you are operating on a network with a slow connection or the latency on your network is high.
If disabled, the file system on the controller is cleared, all the necessary files will be created on the controller and all of the files belonging to the project will be sent to the controller when downloading. The files are not checked for any modifications with disabled option.
If enabled, PLCnext Engineer checks the project files for changes before downloading the project to the controller. Only the changed files will be downloaded after completion of the checks. These checks are more time consuming on slow connections but faster on fast connections. Keep 'Use optimization' enabled when working in a LAN.
Confirm the 'Options' dialog with 'OK'.
The modifications are stored when exiting PLCnext Engineer.