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TOP Server problems reconnecting to S7-1500 after program download

I am using the TOP Server OPC UA client driver to read data from an Siemens S7-1500. Whenever I download a program change to the PLC the TOP Server never reconnects and resumes communications, how can I get the TOP Server to reconnect?

Unfortunately, this is a known issue with the S7-1500 hardware. The TOP Server loses communications because the S7-1500 reboots the Siemens OPC UA server that is running in the PLC after a program edit/download. It has been found that after this reboot the server is overwhelmed by the TOP Server wanting to re-establish communications. 

Currently, the only options we have on the TOP Server side is to slow down how quickly we try to re-establish communications. This can be done by:

  1. Increasing the reconnect and watchdog intervals (found in the channel properties) from the default 5 seconds to 30
  2. In the Device properties, reducing the maximum items per read/write from 512 to a much smaller number. There is no magic number here unfortunately, so we recommend simply halving the value until the issue is no longer observed.

Siemens has provided a firmware update for the PLCs (version 2.5.2) to resolve this issue in their embedded OPC UA server piece.