How to calculate the dB loss for a remote I/O network.
RG6 is .36db/100 feet
RG11 is .17db/100 feet
To calculate maximum attenuation, add all sources of attenuation between the RIO
head processor and a drop adapter; the total loss must not exceed 35 dB (32 dB for
controllers without pre-amps). The maximum attenuation for the system is generally
measured from the RIO processor node to the last drop adapter on the network. The
last adapter usually represents the maximum loss of the entire cable system. There
are exceptions however adapters near the end of the cable system with long drop
cables may have greater attenuation.
Maximum system attenuation at 1.544 Mhz can be calculated as follows:
dB loss = TCA + DCA + TDA + (NOS x 6) + (NOT x 0.8)
TCA = the trunk cable attenuation from the head to the end of the trunk
DCA = the drop cable attenuation, generally at the last drop
TDA = 14 dB, the tap drop attenuation
NOS = the number of splitters in the system
NOT = the number of taps between the last node and the head
Note: The Quantum is obsolete and has been replaced by the M580, the M580 can run the Quantum remote I/O or can be upgraded to the x80 I/O that is Ethernet. For more information on this contact local Schneider office or distributor.