Zener SMARTSTART 6000, Инструкция по эксплуатации

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Network Connections
Technical Manual: Smartstart
®
6000 IMI0042 rev K
Page 15
Modbus RS485
The Smartstart
®
6000 comes standard with Modbus RS485
serial communications. Typical wiring for RS485 shown
below.
The following precautions will help minimize the risk of
network failure:

Use twisted pair shielded communications cable

Each length of cable should have its shield connected
to ground at one end only (recommended at the
computer or controller end)

It is recommended to use two twisted pairs, one pair
for circuit ‘common’, and another pair for balanced
data lines.

The ‘common’ circuit must be connected to all
devices on the bus and connected directly to
protective ground (at one point only, typically near
the master device). ‘Screen’ terminal provides a local
protective ground. (Eg. For cable shield)

To reduce network noise place a line terminator near
each of the two ends of the bus. A 120 Ohm resistor
is recommended for both line terminators. A
capacitor (1nf) in series with the resistor may also
improve performance.

Line polarization (450 – 650 Ohms pull ‐ up and pull
down) is also recommended, typically in/near the
master device.

Avoid laying communications cables adjacent to
power cables.

If possible communications cables should cross power
cables at right angle to each other.

Up to 64 nodes (equipment) may be connected to the
same network without an RS485 repeater.
Modbus Ethernet TCP
An Ethernet option card is available which provides an
Ethernet socket. When the Ethernet card is fitted the
RS485 connection will not operate.
A comprehensive Network Guide is available on our
website: www.zener.com.au or contact us for more
details.
PLC /
Computer or
RS232/485
converter
A
B
Com
A
B
Com
A
B
Com
A
B
Com
ZENER
SS
60
00
ZENER
SS
60
00
ZENER
SS
60
00
120 Ohm
A
B
Com
Com
A
B
Com
Com
PLC /
Computer
ZENER
SS
60
00
ZENER
SS
60
00
ETHE
RN
ET
HU
B