For fiber-optic cables, use the cable and connector type that is appropriate for the fiber-optic ports on the hardware. The type of fiber-optic cable required could be multimode or single-mode and depends on the port specifications, the site's physical layout, and the distance between fiber-optic ports from device to device. It is important that the fiber-optic cable's transmission loss (attenuation) per kilometer is carefully measured and known. Ensure that the end-to-end loss calculation (in decibels) includes all connectors and splices. The transmission loss can be measured with an optical power meter or determined from the cable manufacturer's specifications.
Following are some guidelines for using fiber-optic cable in a DeltaV Control Network:
- Multimode fiber-optic cable is generally used for 100mb/s100BASE-FX fiber-optic communications for up to 2 kilometers and either 50/125 micron or 62.5/125 micron multimode fiber can be used depending upon the specifications for the fiber-optic ports on the hardware. Refer to the cable manufacturer's specifications for the cable's transmission loss per kilometer in decibels.
- Single mode fiber-optic cable is generally used for 1000mb/s 1000BASE-SX (gigabit) fiber-optic communications for distances up to approximately 500 meters and 50/125 micron or 62.5/125 micron multimode fiber can be used depending upon the specifications for the fiber-optic ports on the hardware. Single mode fiber-optic cable can also be used for 100BASE-FX communications. Refer to the cable manufacturer's specifications for the cable's transmission loss per kilometer in decibels.
- Multimode fiber-optic cable has a Modal Bandwidth specification (MHz/km) which is a distance limiting factor for gigabit communications on multimode fiber. Refer to the cable manufacturer's specifications for distances supported for gigabit communications over multimode fiber.
- Fiber-optic cables are terminated with ST, SC, MTRJ, or LC connectors depending upon the physical port that is used on the hardware. Be sure that the fiber-optic cable termination is appropriate for the fiber-optic port type used on the hardware.
- All fiber-optic links should be tested for attenuation with an optical power meter. The entire link, including all assembled cables, connectors and splices from end to end should be measured. This measurement should not exceed the equipment manufacturer's loss budget specification and at least a 3dB margin should be left.
CAUTION!