Cisco doesn’t really have a “3560” manual – their strategy is that all of their equipment is configured/works almost identically across platforms; so any IOS samples for 3560 / 3750 and even 4500 or 6500 have essentially the same functionality for basic operations. The caveat would be the features supported – not all commands work on all platforms and you may need an IOS version for “advanced features”.
You indicated PLC’s are in different subnets – how have you accomplished this?
– Do you have separate VLANs configured for groups of ports?
– Have you currently any way of passing data between subnets (a separate router, or L3 features within the switch)?
– Or have you simply used different subnets on the endpoints; so that logically they are all on their own networks, but essentially they share the common network, and isolated only by configuration limitations?