Dear All,

I am new to S7-1200 programming and I am working on a project which involves communication between an S7-1200 and a KTP Basic Panel (there are no other ethernet/profinet devices - the two connect directly with a cat 6 cable I have confirmed to be good). My problem is that the two refuse to connect with each other despite having set up IPs and the connection appearing in the "connections" selection of TIA portal. The HMI does not display the values I want (it just shows ######## on the number field) and whenever I try to write a variable on the PLC the HMI gives me a "Could not access XXXX on the PLC" error. Both devices accept my uploads. What I am I doing wrong?

One peculiarity I've noticed is that whenever I upload the PLC program to the PLC, even though the new device name is slave_1 the TIA Portal upload manager finds it as slave_3 (a previous name). Does this have anything to do with it?

I am using TIA Portal v17 basic without updates and have also downloaded PLCSIM and the panel images.

Attached you will find the project files on my google drive. The problem appears between the "Slave_1" PLC device and the "Slave HMI" Panel.

[snip]

Thanks a lot,

Thalis Paktitis

Hello Thalis Paktitis,

Same problem we were facing in our system.

We are using S7-1200 PLC, KTP700 Basic HMI and TIA Portal V18.

Downloading to both the devices was working OK but still, the HMI was showing ###

We changed the HMI Device version (Right-click on HMI -> change device/version -> select HMI KTP700 Basic V15.1) to V15.1 and Downloaded it to HMI and now the communication is working and HMI is showing the required values.

Initially, we tried the HMI device versions V18, V17, V16, and V15.0 but did not work.

After follow the Siemens indication in the link:

Connecting older HMI to S7-1500/1200 with newer firmware

my KTP400 BASIC (firmware 17.0) however didn't communicate with S7-1200 (firmware 4.6).

I downgrade the HMI firmware from 17.0 to 16.0 and all works fine. I have TIA19 update 3.

Hope to be useful.

Ciao.