National Instruments 779490-01 Backplane for Compact FieldPoint

The 779490-01 is an identifying part number for the cFP-1804 backplane by National Instruments, designed to connect directly to Ethernet networks. It facilitates a smooth integration with current network infrastructures by supporting autonegotiation at 10 Mb/s or 100 Mb/s communication speeds. It uses a protocol based on conventional TCP/IP for complete compatibility and an RJ-45 connector to enable connections to 10BaseT and 100BaseTX networks.

Event-driven communications and a publisher-subscriber network architecture are two features that the 779490-01 adds to ordinary TCP/IP protocols. This configuration allows one or more client PCs to subscribe to Compact FieldPoint banks' I/O data. In order to minimize needless Ethernet traffic and maximize communication efficiency, the network interface keeps an eye on linked I/O modules and publishes data only when changes happen. To further reduce network burden on analog signals, adjustable deadbands enable value changes within predefined ranges without resulting in data reports.

Programs operating on a PC or embedded controller can directly read and write to the 779490-01 through its DB-9 connector for RS-232 serial communication, which is included in addition to Ethernet connectivity. With 8 data bits, 1 stop bit, no parity, and no flow control, this feature enables a baud rate range of 300 to 115,200 bps.

The 779490-01 has variable power requirements; a 20 W power source is advised, and the supply range is 11 to 30 VDC. In addition to the power requirements of the I/O modules by 1.1 times, the backplane itself uses 6.1 W. A maximum cabling distance of 100 meters per segment is supported by the device, which can supply up to 9 W of power to I/O modules. The module to backplane isolation is rated for continuous operation at 250 Vrms (Measurement Category II) and can tolerate a voltage of 2,300 Vrms for up to 5 seconds, making safety a top priority. This guarantees strong defense against electrical risks.