I-O Display Systems Basic I/O Product - Manual (Page 29)

Setup & Installation 2
2-12(Vol.1)
BASIC I/O to BASIC I/O RS-485 (Multidrop only):
Figure 2-8 RS-485 BASIC I/O to BASIC I/O Multidrop
Figure 2.8 shows one individually shielded twisted pair of AWG 24. Each pair has a ground
wire connected to its shield. These drain wires are then connected to the signal grounds at
each unit. A Separate shield encases the entire cable. The drain wire for this over-all shield is
tied to earth ground at one location. An example of acceptable wire for this application would
be Belden 8162. In a perfect world with no electrical noise and equal ground potentials
everywhere, the ground connection is not required. However, omitting this signal ground in
industrial applications can lead to costly debugging.
These connections are made by placing a 1/4 inch stripped wire into the openings of the wire
clamp terminal block and tightening the screw. This terminal block will accept gauges from
14 to 30AWG.
An alternate means for network connection is to use the 10 pin male connector located behind
the clamp terminal block. This connector mates with Molex shell number 50-57-9005, and
uses pins number 16-02-0103.
In addition to the Host-To-BASIC I/O wiring, the installer should confirm that the network
type switches are set in the correct position: Multidrop, Repeater, or Last Unit.
NOTE: The number of BASIC I/Os that can be networked in a multidrop configuration
before a signal amplifier (An external repeater) is needed depends greatly on external factors.
Repeater networks are unlimited.