Rockwell Automation 2090-xxx Fiber Optic Cable Installation and Handling Instructions - Manual (Page 15)

Fiber Optic Cable Installation and Handling Instructions 15
Publication 2090-IN010C-EN-P – April 2005
SERCOS Attenuation Limits
The SERCOS standard defines different allowable attenuation losses for
both Plastic and Hard Clad Silica fiber optic cables. The differences for the
two types of fiber are due to the drive characteristics of the transmitters into
the different diameters of POF and HCS cables.
The fiber optic transmitter power is measured using a 1-meter length
reference standard cable to an optometer. SERCOS has system attenuation
limits, which are governed by the minimum light power required for proper
operation of the receiver. SERCOS generally includes a bulkhead connector
in the transmitter to receiver path. The table below shows these limits.
SERCOS System Optical Transmission line Specifications @ 650nM
Continuous Light ON Plastic Optical Fiber
(POF) Glass Optical Fiber
(HCS)
Transmitter Min Power -7.5 dBm (uW) -18 dBm (uW)
Transmitter Max Power -3.5 dBm (uW) -10 dBm (uW)
Receiver Min Power -20 dBm (uW) -22 dBm (uW)
Receiver Max Power -5.0 dBm (uW) -7.0 dBm (uW)
System Attenuation limit POF Cable >= 29.6 m HCS Cable >= 200 m
Max point to point
attenuation 12.5 dB 4.0 dB