Kuka KR C4 Compact - Siemens S7 1200 Plc Connection

Thats not how to connect them.
You should have "Device description files" / GSD files for the KUKA profinet and you load them in TIA portal.

So in TIA, in the tree under "devices and networks" you are able to see your robot controller. You assign a IP address and a profinet name for this controller in TIA portal.

Then you map your PGNO and EXT_START and PGNO_VALID and DRIVES_ON and all others to some Profinet addresses in Kuka WorkVisual software.

Once this WorkVisual project is deployed to the KUKA controller you are able to see the tag values in TIA protal and write the outputs.

In the robot controller you can have EXT_START declared as INPUT[1000] ... you map this to profinet_input nr 1. In TIA portal you set up the KUKA controller to start taking addresses starting from byte 100 and then the first bit of this byte you know is your EXT_START with the address Q100.0
Its going to be an output on the PLC side of things.

So in summary. Get the GSD files for Profinet and add them to TIA portal (You can get them from inside the controller if you minimize to the windows environment or from inside the WorkVisual program folder). Add the new device KUKA controller. Map all the inputs and outputs you need. Check the Integrator manual signal diagram to figure out what bits you need and when to switch them.

which device description file you need, depends on what fieldbus you use

GSD files are for ProfiBus.

GSDML files are for ProfiNet (where ProfiNet is "profibus over Ethernet")

but... though incorrect, pretty often term is used loosely so "GSD" term is still sometimes meant to refer to GSDML

just like term "fieldbus".... the term "fieldbus" comes from actual bus topology. ProfiBus, CanBus, DeviceNet, CompoBus, DH+ etc are all examples of a real bus (all derived from 422/485 serial bus). in a fieldbus nodes are daisy chained (electrically in parallel) by tapping into same cable - without additional electronic devices.

and still, Ethernet networks are also often called "fieldbus" even though they are not really a bus, they are connected differently and require additional hardware (such as Ethernet switch). in a network of 20 nodes, terminals of those 20 nodes are not simply wired in parallel as it is the case of the bus.

KUKA distributes device description files with WorkVisual and are normally found in folder such as:

C:\Program Files (x86)\KUKA\WorkVisual 6.0\DeviceDescriptions

the problem is that you are trying to do something you are not trained to do. KUKA offers fieldbus training which is 4 days just for one type of network (ProfiNet for example). book the course, take a week off, spend the $3000 and you will learn all you need - and have chance to ask trainer any questions. same goes for Siemens PLC training...

short of taking such courses, or hiring someone knowledgeable, you are forced to stumble in the dark.... so may as well forget about connecting them 'effectively'. you will bump, trip and fall plenty of times until you stumble upon something that works. getting there may be a long road since forum is not a substitute for formal training.

you can get answer to a quick question but nobody is going to give you complete step by step instructions for your application to spend time teaching you something that takes weeks to acquire. so you need to pick and choose what are you asking, may want to check previous discussions to gather some info...

do you want robot to act as master? and plc to be the slave? or the other way around? PLC must be master if you want to exchange both standard IO and also safety signals.

whichever side is acting as a master, that side must have some sort of a "scan list". that is basically a list/configuration showing info on each slave. this way master knows all the slaves...and can start talking to each of them. each entry in this list includes node address, type, size of IO etc. slaves know nothing. they may see other slaves and hear traffic meant for other slaves but they do nothing until asked. they only respond when spoken to, and master does all asking and ordering around...

and for the record... you did not show even the robot side configuration. all you have shown is what nodes WorkVisual can see (network scan). this is not configuration and it says nothing about what the actual settings are.

so if you want PLC to be the master, you need to configure it like that. it means you need to import KUKA GSDML file(s) into TIA portal. that just adds them to the library of all devices. then you still need to insert it from the library into the PLC project.

btw. one PLC can connect to multiple robots. in this case you would need to create new instance for each of robot (insert it from library). and each would still need to be parametrized.

this is an example of Communication settings on the robot side. one still need to map IO, transfer project to KRC and activate it.... then the robot side is done. and one has to do equivalent setup on the PLC side but that one is of course to be setup as a master.

each platform uses own terminology....

in case of TIA portal, device library is called "hardware catalog"
in case of WorkVisual it is called "DTM catalog" etc.

but the idea is the same. if you want product to act as master, you need to populate the library. then you can take things from library and add into your project...

what you see here in the middle of the screen is a "scan list" (a version as it appears in TIA portal, it will look different in other software products but serve the same purpose).