Which software for S7-300

[ceilingwalker]

This is what I am connecting to. I have no idea if this is significant or not. The ESA VT505 (HMI) is the cable entering the PLC at the bottom. Then I am plugging in at the DB9, of course.

 

[JesperMP]

Re the photo from the online information, it appears that the version of the programming software is not listed. In the newer S7-1500 you can see the program version - I don't work with TIA software with S7-300 so it was a guess from my side that you could see the program software version.
But I think that the problem is that the program is made with STEP7 classic.

Re the photo of the connector.
It is fine that you connect to the 'piggy-back PG connector'.
In principle the termination switch is in the wrong position. It should be in the ON position for the end of the cable. Same for the connector on the ESA panel (unless the cable continues in a daisy-chain to other devices).
The reason that the ESA panel and the programming software works ok (except for the program version issue) is that the MPI bus on the 312 CPU runs at 187.5 kbps, and at that speed it is quite resilient against wrong cabling. Is that even a proper MPI/Profibus cable ?

 

[ceilingwalker]

With my extremely limited knowledge of Siemens PLC', I wouldn't know proper from improper, being completely honest. If you mean my connection cable, that should be correct, I confirmed with Siemens vendor and tech support.