Access with password stops working with firmware V3.1 and up (S7-1500)

[StefanoRivolta-Previero]

When switching to Firmware V3.1 and up or to PLCsimAdv V6.0 and up, the HMI access with password doesn't work anymore.

It's likely due to the changes Siemens implemented to the users, passwords and access control in V3.1. Even with Legacy Access enabled, and the passwords set for Full Access and HMI Access it doesn't work. I've tried it on both PLCsimAdv V6.0 and on an actual CPU S7 1516F-3 with both firmware V3.0 and V3.1. When V3.1 is loaded it stops working, even if the CPU in the project is set as FW V3.0.

When the protection level is set to 3 or lower (HMI Access, no password) and the project FW is set to 3.0 it works fine (without password). When the project FW is 3.1 and you give the HMI Access rule to the Anonymous user, it also works fine (without password). The culprit seems to be the password.

Also, I'm not sure how it should work in general with FW >3.1 and without legacy access (access levels), as there doesn't seem to be a way to send to the plc both a username and a password. Even the Siemens documentation is a bit weird on this (https://support.industry.siemens.com/cs/document/109955142/configure-an-hmi-connection-to-an-s7-1500-cpu-with-fw-v3-1?dti=0&lc=en-ME)

If you look at point 2 it seems to suggest that you still need to use the legacy full access control password even if you then disable the legacy access levels. Weird.

Regardless, I'm not really experienced enough to figure it out myself. If you need help recreating the issue, I'll gladly help. You can also send me a DM.

Thank you