Micromod MOD: Remote I/O Modules for use with 2020N Remote I/O Interface Module - Manual (Page 15)

Remote I/O Modules
ELECTRICAL CONNECTIONS
3.4 REMOTE I/O INTERFACE BUS CONNECTIONS
The remote I/O Interface (CS 31) bus is a shield twisted pair RS485 connected as described
below. One 2020N Remote I/O Interface module is required for each remote I/O network.
REMOTE I/O INTERFACE RS485 SERIAL NETWORK
Bus Master 2020N Remote I/O Interface Module (end of bus)
Bus Slaves Remote I/O Digital Modules
Maximum Length 500 meters (1600 feet)
Baud Rate 187.5K
Number of Addresses 32 (31 slaves + 1 RIO master at address 0). Star connection
of the bus is forbidden!
Termination 120 Ω, 1/4 Watt resistor required across the two conductors
at each end of the cable (2 shipped with RIO module)
Shield Required over 50 meters (160 feet). The shield of the bus
must be connected to the earth near the master. The shield
is connected to the earth through a capacitor 1 nF class Y.
Isolation The bus is opto-isolated from all units.
REMOTE I/O INTERFACE CABLE
Indoor
Beldon #9182
Indoor Plenum Beldon #89182
Underground Beldon #9815 twisted twinax
Outdoors above ground NOT recommended
Wiring See connection guidelines
When noisy elements are in the area of the cabinet, it is better to connect the bus' shield to
the ground via a capacitor 1 nF class Y directly at the access of the cabinet according the
following diagram.
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