How to Switch HMI communication to 2 redundant CPUs.

Hi everyone, I'm posting this to ask for help with a redundant system with two Siemens 400 H CPUs and a TP 1200 HMI panel. Basically, when CPU A goes to sleep, the panel stops communicating, and I can't change the panel's connection to CPU B. Does anyone know how to do this? I tried modifying a script I found online, but it doesn't work, and I don't really know how to accomplish this IP communication switch.

This solution works for sure. 
Check the IP address settings in the script etc. 
Check the script execution frequency.. 

In the past something similar happened to me.
Display the PLC A and PLC B both tags to every page( make it transparent) So that the script tags will be updated every time. 
 

dchartier

Hello Alessandro;

If your HMI is a Comfort panel (6AV6124-0MC01-0AX0, for example), it supports scripts in VBA and Java. 

The following application note shpws how you can connect a singl;e Comfort HMI with 2 redundant S7-400H CPUs through a changeover script.

https://support.industry.siemens.com/cs/nl/en/view/96837136

Hope this helps,

Daniel Chartier