Honeywell RS-485, Руководство по установке, Страница: 9 / 18

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mandatory for proper data transfers. Individual wires in a cable bundle are marked with
colored stripes to make the task easier. The "A, B, Y, Z" notation shown here is more
prevalent in the industry, and the Metretek RS-485 adaptor board conforms with this
practice. Some manufacturers of RS-485 devices may deviate however, and in such cases
triangular symbols for the transmitters and receivers should be referenced for guidance.
Figure-7 goes a bit further to illustrate a typical full-duplex system as it would be wired
in the field for the Metretek RS-485 end. Note that the cable has three twisted pairs, and a
shield connection. The drain wire from the shield connection must only be attached to
earth ground at a single point to avoid potential ground loops.
Figure-7
Shielded Cable Attachment
Figure-8 illustrates full-duplex connections for the user end point device. Naturally, this
connection scheme appears essentially the same as that shown in Figure-7.
mandatory for proper data transfers. Individual wires in a cable bundle are marked with
colored stripes to make the task easier. The “A, B, Y, Z” notation shown here is more
prevalent in the industry, and the RS-485 adaptor board conforms with this
practice. Some manufacturers of RS-485 devices may deviate however, and in such cases
triangular symbols for the transmitters and receivers should be referenced for guidance.
Figure-7 goes a bit further to illustrate a typical full-duplex system as it would be wired
in the field for the RS-485 end. Note that the cable has three twisted pairs, and a
shield connection. The drain wire from the shield connection must only be attached to
earth ground at a single point to avoid potential ground loops.
Figure-8 illustrates full-duplex connections for the user end point device. Naturally, this
connection scheme appears essentially the same as that shown in Figure-7.