Connect the Modbus/Ethernet Cables
Top and Bottom View
- Connect an Ethernet cable with RJ45 plug to the Ethernet port (A) on the top or bottom of the cabinet.
- Connect the Modbus cable with RJ45 plug to the Modbus port
(B) on the top or bottom of the cabinet.
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2-wire or 4-wire shielded twisted pair cables must be used for Modbus connections. Use a cable for Modbus serial link (RJ45 to RJ45 or RJ45 to free wires depending on the Modbus controller characteristics).
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The Modbus port is optically isolated. The Modbus port’s ground is not connected to any other ground.
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Install 150 Ohm termination resistors at each end of each bus if the buses are very long and operate at high data rates. Busses under 610 meters (2000 feet) at 9600 baud or under 305 meters (1000 feet) at 19200 baud should not require termination resistors.
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Install 400-650 Ohm bias resistors at or inside the system controller; one from D0 to ground and one from D1 to +5 VDC.
Example: Modbus 4-Wire on RJ45 Connector
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- If more than one RPP must be connected to the Modbus controller,
use an RJ45 Modbus hub or splitter block.NOTE: Wiring should be done in accordance with local wiring codes. Route signal cables separately from power cables to reduce noise.