Yes, there are two ways:
1). You can pull your data, from DRO and other functions, in a Brain and send it over TCP Modbus (RTU Modbus protocol).
2). If you want more than if mach3 running or not, axis positions, Feed rates, spindle speed (or other standard OEM data that has DRO's or LED's),
then you would need a plugin. But, from VB you can pull some data that the Brains "doesn't see", and then put it into a holding register like a DRO,
and grab-send with Brains over TCP modbus.
If you want deeper functions than the standard OEM user stuff (buttons, leds, dros, tickers, labels), and VB driven other functions/status/parameters,
then you will have to get to that data with a plugin hybrid with Brains/Modbus.
Further, if your SCADA does't do Standard RTU TCP Modbus, but does communication bus(s) like: (Profi-bus, CAN-bus, Device-Net, Blue-Hose, K-sequence, Direct-net...etc.)
then you would need to have a hardware COM card of that type, that allows developers to access its DLL so you can send Mach3 data over your COM card.
scott