Map your ProfiNet I/O in WorkVisual. Then assign those $ system signals to $OUT and $IN numbers that fall into that mapped range.
imagine you are put in charge of some land where you need to establish some transportation service between two cities (bus, boat, rail, airplane or whatever). you need to create schedule, establish route, create terminals (bus stops) etc.
the equivalent thing in automation world is called configuring network or a fieldbus. so lets assume it is a bus service.
first you need is the road system (busses do not travel well through wilderness).
in the automation world, equivalent to this is creating suitable physical network (wiring) between nodes. each network will have own set of products (media, connectors, terminators, splitters, switches, repeaters...).
then you need to do some configuring (make schedule and open ticketing services at each of the bus stops, hire bus drivers etc.) or in this case both KRC and PLC need to be configured so that they can work together and ensure service (circulation of messages).
the next one is to actually let the passengers in. that is what your variables are. once you have a working bus service, it is easy to have someone seated into one of many bus seats. you can have bus service operate without any passengers too, but reasonable thing is to get some (maybe 80% or so) of the seats occupied...
adding one new passenger (one more variable) does not mean bus schedule etc need to change. service need to be designed to handle traffic and have some spare capacity.
so...
1. road system - create physical network with valid and matching network settings
2. bus capacity and schedule - configure PLC and ProfiNet master and KRC as ProfiNet slave, specify size of message (bus size) to be transferred.
3. ribbon cutting ceremony - map the message data to PLC and robot I/Os
4. run the bus line - copy values of some variables (whatever you need) to/from robot I/Os that are serviced by the fieldbus. anything that leaves one terminal (KRC or PLC) via OUT of that terminal, enters the traffic system and nearly instantly appears at IN of the other terminal. you can transfer as many variables as message block will allow. you can pick and choose which bits in message to use (same as choosing bus seat) but the order of data is same when message is delivered (no seat swapping while bus is driving).
you are welcome
