Fiber optic networking

Fiber optic networking

Overview

Fiber optic signal transmission for process monitoring and control has been progressively adopted in recent years. In critical applications with very high requirements for data availability, it has become the transmission technique of choice. This is due to the many advantages that fiber optic signal transmission offers over copper based systems:

  • Maximum resistance to interference, even in applications with extreme levels of electromagnetic interference
  • High grade electrical isolation between stations
  • Long transmission distances with extremely high data rates
  • The number of stations is not limited by the electrical properties of the communication interface employed
  • Improved security and reliability

This results in a significant gain in performance and immunity to interference for the data communication infrastructure, without having to allow for complex surge protection measures, shielding and equipotential bonding concepts.

NSPI fiber optic modems provide complete physical layer network solutions for both open standard networks and the communication/control networks of most of the major global PLC and control system suppliers. NSPI’s standard digital protocols and analog signals include:

  • Digital: Industrial Ethernet, Profibus, Modbus, Modbus Plus, ControlNet, Data Highway Plus, DH-485, Genius, Remote I/O, RS232/484, Reliance R-Net
  • Analog: 4-20mA, 0-10V

NSPI has developed and qualified various fiber optic modems for nuclear power generation applications.

Fiber Nuclear qualified analog fiber optic data linkThe NSPI nuclear qualified analog fiber optic data link is designed to convert a 0-10VDC signal into a fiber optic signal for transmission, via a fiber optic cable, up to 10,000 ft (3,000 m).  Once received, the fiber optic signal is then converted back into a direct proportional analog 0-10VDC signal via a receiver unit.  No field adjustments are required, simply apply power, connect the two units with fiber optic cable and supply the input signal to the transmitter.

NSPI’s analog fiber optic data link has been qualified to meet the seismic requirements of IEEE 344-1987 and mild environment requirements of IEE 323-1974/1983.

Model Description
N9387 & N9388 Qualified fiber optic data links

Nuclear qualified analog fiber optic contact closures

The NSPI fiber optic contact closures can be used to transmit contact closure data up to 16,000 ft (5,000 m) with 200µm cable.  The DIN-Rail mount enclosures enable easy installation on industry standard hardware. The FOT-CC transmitter provides a closed contact signal to the FOR-CC receiver, which activates a single pole, double throw relay.