EURA SD20-G Series, Manual

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SD20-G Series
345
Servo drive
PC/PLC
R
ea
d
p
ar
am
et
er
v
al
u
e
Servo drive
Servo drive Servo drive
W
rit
e
p
ar
am
et
er
v
al
u
e
R
ea
d
p
ar
am
et
er
o
rd
er
W
rit
e
p
ar
am
et
er
o
rd
er
Fig 10-1-1 Connecting diagram of field bus
RS485 Half-duplex communication mode is adopted for servodrive. Daisy chain structure is adopted by 485
Bus-line. Do not use 'spur' lines or a star configuration. Reflect signals which are produced by spur lines or star
configuration will interfere in 485 communications.
Please note that for the same time in half-duplex connection, and only one inverter can have communication
with PC/PLC. Should two or more than two inverters upload data at the same time, then bus competition will
occur, which will not only lead to communication failure, but higher current to certain elements as well.
3 Grounding and Terminal
Terminal resistance of 120

will be adopted for terminal of RS485 network, to diminish the reflection of signals.
Terminal resistance shall not be used for intermediate network.
No direct grounding shall be allowed for any point of RS485 network. All the equipment in the network shall be
well grounded via their own grounding terminal. Please note that grounding wires will not form closed loop in any
case.
A+
B-
The distance
should be less
than 0.5M.
Master
Slave 1
Terminal
resistor
Slave 2 Slave 3 Slave 4
Terminal
resistor
Fig 10-1-2 Connecting Diagram of Terminal Resistance
Please think over the drive capacity of PC/PLC and the distance between PC/PLC and inverter when wiring.
Add a repeaters if drive capacity is not enough.
All wiring connections for installation shall have to be made when the inverter is disconnected from power supply.