Hitachi SJ2002 Series Instruction Manual page 242

B–4
Connecting the Inverter to ModBus
4. Terminate Network Wiring - The RS-485 wiring must be terminated at each
physical end to suppress electrical reflections and help decrease transmission errors.
The SJ200
you will need to add termination to the inverter if it is at the end of the network
wiring. Select termination resistors that match the characteristic impedance of the
network cable. The diagram below shows a network with the needed termination
resistor at each end.
5. Set Inverter OPE/485 Switch - The inverter serial port accepts a connection to either
the inverter keypad or the network. After removing the keypad, you will need to set a
DIP switch on the inverter to configure the port for ModBus communications. Setting
the switch will require removing the front housing cover. Remember to power OFF
the inverter before removing the cover or changing the DIP switch setting. Refer to
"Front Housing Cover" on page 2–4
Locate the OPE/485 DIP switch as shown in the figure below. Carefully move the
switch to the upper position labeled "485" (slide in direction of arrow). Then replace
the front housing cover.
At this point the electrical network connection is complete. The next step will show
how to configure parameters and settings related to ModBus communications.
communications port does not include a termination resistor. Therefore,
2
ModBus
Network
SP SN
Host device
SJ200
SJ200
2
for detailed instructions.
SJ200
2
2
SR 485 TM
SK
OPE PRG