Milling spindle on/off during Powermill krl program execution in KSS 5.6.12

well that was fun but how about picture of top side of the KUKA PC and copy of IOSYS.INI?

empty green socket on nearest card is DeviceNet. Since this is built in option for every robot (part of MFC) it can only work as a DeviceNet master. you can DeviceNet slaves and this is easy to setup.

card in the back with purple cables is ProfiBus. This is standalone board and has more features than MFC DeviceNet. it can be either master or slave or both, it supports coupling etc.

so you have two options to add I/Os to your robot system.

next question is what I/O modules you have there (if any).

picture in post8 shows purple cable cut off...

is there any electronics mounted on the robot arm?

there seem to be three grippers connected to Festo-CPX etc.

using DeviceNet would be the simplest since all configuration is done by editing plain text, no special software is needed. check forum, this was discussed many times...

by the way:

for milling sometimes a vacuum cleaner is also very helpful

The purple cables are ProfiBus. Do they connect to anything, or are they just chopped off?

I agree with Panic, your simplest route to I/O will be to use DeviceNet on the X801 connector (ISA card closest to the printer&serial ports).

You could perhaps use the serial port, and send commands to an Arduino that way. That would be cheaper, but not easier, and certainly less industrially-robust. There's a lot of old forum posts about using RS232 on KRC2s.

maybe, you need to read the files. there is IOSYS.INI which hints at some brands. more could be found in bus specific INI files. they are all in same folder.

do you have a screen shot about your output modules?