Is it possible to network two S7-315 2DP/PN PLCs via Wi-Fi WDS?

Question

Automation

Good day. The enterprise has several controllers connected to each other in a network with a conventional 5e UTP cable in a chain. Recently, another controller was installed, but the distance to it is + - 100 meters and it is physically impossible to lay the cable in a short time, you need to connect it to the rest of the PLCs as soon as possible. If I connect a router to each controller and set the wireless bridge to WDS, will the 2 controllers connected in this way make friends? (i.e. simulate a cable connection). I know, with a PC it's all without problems, but I haven't done this with Siemens yet. Maybe someone has already encountered a similar situation? Thanks in advance for your reply!

Answer 1

Depends on the transfer protocol, most likely. We tried to deploy Profinet "on the table" on a "household" router - the router does not pass the corresponding packets (checked with WireShark). But this is Profinet.
At the same time, during commissioning we very often hang a router in a cabinet with a PLC, and you can safely walk around the shop looking at the equipment being adjusted and monitor the progress of the program in the controller. That is, S7-connection will most likely work.

Answer 2

... after all, cable is more reliable...
Imagine if someone "drops" this Wi-Fi on the working equipment!

Answer 3

It is also possible via WDS, it is possible as a client to the AR. It is possible through a regular (household) Wi-Fi, it is possible through an industrial one. It all depends on what you want to get in the end:
1. Just monitor the CPU tags and remotely upload the program / diagnose the status - you can through the "household" Wi-Fi. Tried, works. On the commissioning site, we often put an ordinary router (like an AR) directly on the control cabinet, and we ourselves test it near the equipment. All this is the so-called IT-traffic.
2. The CPU participates in RT/IRT communication. "Household" Wi-Fi will not work - it does not support exchange protocols. Need "industrial" Wi-Fi. Otherwise, there is no guarantee that packets will arrive at the specified time. The result is communication errors in the CPU program. Well, and if it is also SAFETY-data - put out the light! It's almost impossible to start...
So what do you have?