User`s manual

ManualsBrandsZ-World ManualsComputer equipmentXP8900

PK220042 s System Development

Developing an RS-485 Network

The two-wire RS-485 serial-communication port and Dynamic-C network

software allow network development. Screw terminal strip J1 provides a

half-duplex RS-485 interface.

The RS-485 signals are on

screw terminals 18 and 19.

The PK2200 and/or other control-

lers can be linked together over

several kilometers. When config-

uring a multi-drop network, use

single twisted pair wires on all

controllers to connect RS-485+ to

RS-485+ and RS-485- to RS-485.

A diagram of a two-wire RS-485

network is shown in Figure 4-5.

Any Z-World controller can be a

master or a slave. A network can

have up to 255 slave controllers,

but only one controller can be the

master.

In a multidrop network, termina-

tion and bias resistors are required

to minimize reflections (echoing)

and to keep the network line ac-

tive during an idle state. Only the

first and last board on a multidrop

RS-485 cable should have termi-

nation resistors. Therefore, when

networking multiple boards via

RS-485, remove termination re-

sistors from all boards in the net-

work, except for the first and last

board of the network.

Only a single, solid conductor should be placed in a screw clamp termi-

nal. Bare copper, particularly if exposed to the air for a long period

before installation, can become oxidized. The oxide can cause a high

resistance (~20 ohm) connection, especially if the clamping pressure is

not sufficient. To avoid oxidation, use tinned wires or clean, shiny copper

wire. If you are using multiple conductors or stranded wire, consider

soldering the wire bundle or using a crimp connector to avoid a later loss

of contact pressure to a spontaneous rearrangement of the wire bundle.

Soldering may make the wire subject to fatigue failure at the junction with

the solder if there is flexing or vibration.

GND

PIN01

PIN02

PIN03

PIN04

PIN05

PIN06

PIN07

PIN08

+5V

PIN09

PIN10

PIN11

PIN12

PIN13

PIN14

PIN15

PIN16

GND

+DC

GND

HV01

HV02

HV03

HV04

HV05

HV06

HV07

HV08

HV09

HV10

HV11

HV12

HV13

HV14

485+

485–

PROGRAM

RUN

GND