You have two options:
1) Fieldpoint
2) PXI
The fieldpoint system could be configured to be controlled via a RS-485 network. Unfortunately, the types of available modules are somewhat limited.
The types of modules currently include: analog input (thermocouples, voltage, current, rtd,strain gauge, etc...), analog output, discrete input, discrete output, counter, relay, pulse width, pulse generator and a few others. Unfortunately, we do not have any modules dedicated solely to wave form generation.
You could probably use a relay module to provide switching capability and an analog module to convert an analog signal to a digital signal.
The second option is to purchase a pxi system. The pxi system can give you all the capabilities you listed (wavefor
m generation, switching and a/d conversion). However, there is no real RS-485 control capability.
With a pxi system, however, you could have it be a standalone system (processor and os included). Or, if you'd rather control it from a remote computer, you could link up to it with a MXI-3 bus/connector.
After this long explanation, I guess my suggestion would be to use a pxi system:
Chassis (PXI-1000B)
Controller (PXI-8176)
Wave Form Generator (PXI-5411)
Switch (PXI-25xx)
A/D board (Contact Sales)
Let me know if you have any other questions. Thanks.