Hello
I have a Siemens S7-1200 PLC, my robotic arm does not have input / output modules, with this PLC and together with the KRL output programming, can I control any output such as the gripper or another actuator?
Hello
I have a Siemens S7-1200 PLC, my robotic arm does not have input / output modules, with this PLC and together with the KRL output programming, can I control any output such as the gripper or another actuator?
you can control any output you like ... it is just a variable in memory (a BOOL array to be specific).
to control gripper or actuators somehow those values need to be associated with physical outputs.
there are different ways to go about this....
direct way is to have some I/Os added to your controller (internally or externally). this is most practical since you don't have to wait for some other equipment to power up, there is no added latency etc.
indirect way is to send some of those signals to another device that has some spare I/O.
this could be some PLC or another robot controller. then you would need to add some code or at least do correct mapping at that node to transfer signals from your robot controller to physical I/Os (or pass them again to another node). this requires some sort of fieldbus that both nodes can use.
normally S7 PLCs can use ProfiNet or ProfiBus. so if your PLC has one of those options, you require same option on the KRC. but that is not all. the role of each node on that bus must be compatible too. this is the way device behaves on the bus or network. some nodes can only act as master, some can only act as slave, and some can be either mater or slave, finally some can be both master AND slave at the same time.
the actual terminology may be different from one brand to another but the idea is the same.
so instead of master/slave, you may also often find scanner/device, or controller/adapter etc.
so for two nodes to exchange data, one has to be a master and other must be slave. two slaves cannot talk to each other. two masters cannot talk to each other. but they may still exchange data if there is some intermediate node that replaces missing role as long as it can do data forwarding on behalf or your nodes.
in fact there is a class of such products which are simply known as bridge or gateway. some companies specialize in making just such products for variety of different networks.
https://www.anybus.com/products/gateway-index
in case of KRC4, ProfiNet is available as a paid option. it comes in two flavors:
M/S can be both master and slave
-/S or can only be slave or "device" and it costs less than M/S version
when interfacing KRC to a PLC normally PLC is the master and robot is slave. if using not only ProfiNet but also ProfiSafe that arrangement is mandatory. hence for most cases cheaper version is fine.
but if you want to use ProfNet to have direct control over some devices such as I/O, then you M/S would be a better choice.
another option would be to find some suitable gateway that can connect both products.
we already saw that PLC is normally ProfiNet master so a gateway we would need to act as a ProfiNet slave.
KRC normally uses EtherCat for adding I/O. EtherCat is already included in every KRC4 and KRC5 system since it used also for drives etc. But when it comes to I/Os, KRC4 only acts as an EtherCat master. therefore gateway would need to have port that works as EtherCat slave.