NI CFP-2120 is a Compact FieldPoint real-time controller in the cFP-21xx family. NI identifies cFP-21xx as the cFP-2100, cFP-2110, and cFP-2120, and describes a Compact FieldPoint system as one cFP-BP-x backplane, one cFP-21xx controller, and one or more I/O modules plus connector blocks or accessories. This confirms the cFP-2120 is the primary controller in the system rather than an I/O module or connector block. Source: https://docs-be.ni.com/bundle/371380b/raw/resource/enus/371380b.pdf
The controller is a real-time embedded device intended to run the LabVIEW Real-Time Engine and execute applications without a host PC. For networking, NI specifies IEEE 802.3 10BaseT and 100BaseTX Ethernet with auto-negotiated 10 Mbps or 100 Mbps communication and a maximum cabling distance of 100 m per segment. NI also documents 128 MB nonvolatile memory and 128 MB DRAM for the cFP-2120, with nonvolatile memory rated for 300,000 writes per sector. Source: https://docs-be.ni.com/bundle/371380b/raw/resource/enus/371380b.pdf
Model-specific connectivity distinguishes the cFP-2120 from other cFP-21xx controllers. NI specifies three RS-232 serial ports and one RS-485 serial port. The RS-232 ports support 110 to 115,200 bps, 5/6/7/8 data bits, 1/1.5/2 stop bits, odd/even/mark/space parity, and RTS/CTS, XON/XOFF, or DTR/DSR flow control. COM 4 is the RS-485 port; NI states it is designed for four-wire mode and does not recommend two-wire operation. The RS-485 port supports 110 to 115,200 bps, 100 Vrms maximum continuous isolation, and 740 Vrms dielectric withstand for 1 minute. Source: https://docs-be.ni.com/bundle/371380b/raw/resource/enus/371380b.pdf
