Hello forum,

I have a peculiar issue in a project I'm following.
I have a project with TIA Portal v18 Upd5 with 7 PLCs (various 1500 models) and 2 wincc servers in redundancy.

All licenses are accounted for.

I managed to do the first download to the pair of servers and all was working fine.

All subsequent downloads stopped working but in a way that I do not understand.

When I start the download (only-changes, full download) both from context menu of the RT or from the Extended download button, the popup for download options appears, I set everything up correctly like the first download, but when I press Load TIA Portal goes from "Start download to device" to "Loading completed (errors: 0; warnings: 0)" in like 10 seconds and no actual operation is done on the servers themselves.

I actually tried also deleting the project folders downloaded to the servers originally but without result.

I tried rebooting all machines but nothing is working...

The engineering station and servers reside on different subnets with a gateway in between.
Simatic Shell is working correctly using multicast proxy and I added the non-local subnet to the firewall configuration of the various windows installs on the server and engineering stations on the SIMATIC related items following a manual I found on the Knowledge Base.

I don't understand what is happening, even Event Viewer shows no errors...

Good morning,

I already had a look at the FAQs and nothing seems to help because I already did all those things myself to try and fix the situation.
This is not my first rodeo with WinCC and TIA Portal being sligtly annoying to deal with when things aren's exactly by the book let's say.

We did a few more tests in the following days from the original post and we found that the braking action in the whole scenario is either a compile changes or a download changes.

As soon as one of these operations is done the project behaves in the way described in the previous post, no download is possible anymore, both download changes and download all are broken.
The same behaviour is observed in both scenarios where the correct popup for download appears, settings are made for reset and autostart etc. but then after starting the download, about 10 sec later Download Completed (errors: 0, warnings: 0), which is not true because no data was sent to either machines.

This behaviour is observed also when redundancy isn't a factor by disabling redundancy in the WinCC Project.

The ONLY way to fix the problem and consequently the only way to download the WinCC project to the servers is a FULL compile and a FULL download, each time.

Using Wireshark on the connection between the engineering station and one of the servers I was able to detect a SMB related error, something regarding a LOCK NOT GRANTED.
I assume that when TIA wants to download a project changes, it locks the project file in the server to monitor the project for what changes to apply to the destination server.
Something is happening there but I don't have the expertice to dive any further in the problem.

This stems from the fact that our access to the infrastructure topology and details is very limited as the client company is extremely reluctant on sharing details and following external guidelines.

I made them aware that a system built as they have, may have problems because the best-practices guidelines from Siemens were not followed and their answer to me was that nobody in their right mind puts an engineering station on the same net as a runtime.
But then on the plant next to this one we are commissioning, they have all machines on the same subnet, clients, servers and eng. stations.... go figure...