Hi
Robots can act as master/slave at the same time. If two (or more) robots are connected to same bus, you just have to make sure you change the address of the masters so that two masters are not using the same address.
If your Anybus device is Profibus slave - DN master, I think you should define your robots as slaves. Then it might be possible for Anybus master to connect to both slaves (robots). I’m not familiar with the Anybus device, but at least their brochure says it should be possible 
The configuration Klaus sent is correct, but with that configuration robot acts as a master for the Anybus device. If you want to run your robot as a slave, you should change the unit type parameter to DN_INTERNAL_SLAVE, like this:
EIO_UNIT:
-Name “BOARD11” -UnitType “DN_INTERNAL_SLAVE” -Bus “DeviceNet1”
IRC5 uses the same address for the master and the slave, so if your robots DN master is defined to use address 2, the slave will also use address 2. Therefore you should change the address of the second robot for example to 3. It can be changed under I/O parameters - Bus - DeviceNet1 - DeviceNet Master Address.
Please tell how it works as I’m also a bit interested in this Anybus converter
And for the voltages… You should have all V+ connected together and all V- together, but make sure you feed the voltage only from one place. As default the DN voltage is connected to one of the IO-unit connectors inside the IRC5 cabinet door (comes from XT31 connector), so if you have several robots in the same physical bus, you can detach voltage feed from other robots and leave only one connected.
Good luck!
-Osku