Modbus TCP Single port server can support redundant function?

Hi.

I'm using S7-OPENMODBUS/TCP (REDUNDANT PN-H) library. I'm tesing MODBUS TCP communication by using redundant CPU 410-5H (clients) communicate with SENTRON PAC3200 (server). The server is connected to integrated port of 2 CPUs via ethernet switch.

Currently facing a problem that only one connection (0A) is established successfully and another (1A) is failed. When i disconnect the ethernet cable of 0A connection,  after a minute, connection 1A established succesfully.

I believe that is not normal for a redundant system. Is it because of the sever (PAC3200) only has one port (502) which caused the re-establish connection take longer time ? under normal condition both connection 0A & 1A suppose to be establish successful?

@Wüstenräuber Understood. Thanks for your support.

@Kaulquappe Appreciate for the information.

Hello,

I tested successfully the simultaneously establishing of 2 connections between one Sentron PAC 3200 (Port 502) and S7-414-5H PN/DP Redundant H-System. I used the internal Ethernet Port of PAC 3200 without additional Profinet-Modul.

Con 0A -> PAC3200 (Port 502)

Con 1A -> PAC3200 (Port 502)

I used latest firmware V 4.2.1.

As mentioned in

https://support.industry.siemens.com/tf/ww/en/posts/simultaneous-profibus-and-modbus-tcp-ip-communication-with-pac-3200/96227/?page=0&pageSize=10 

by Mr. Emergency this is possible from firmware version V 2.3.5 on.

Greetz Bachgeist