LEGRAND 30 KVA, Installation Manual

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8.5. RS485
RS485 with MODBUS protocol is used in a wide range of automation systems for Industrial Process monitoring or for
Building Management Systems. This communication link allows monitoring UPS status and measurements with such
systems.
The RS485 differential line consists of three pins:
•
A is inverting pin (TxD-/RxD-)
•
B is non-inverting pin (TxD+/RxD+)
•
Middle Pin is reference pin (optional GND)
Middle Pin is the reference potential used by the transceiver to measure the A and B
voltages.
The B line is positive (compared to A) when the line is idle.
Communication Parameters
Baud Rate 2400
Data Bits 8
Stop Bits 1
Parity No Parity
Flow Control No Flow Control
Communication Type RTU
Tablo.12
MODBUS END JUMPER (J4): If the UPS is at the
end of the bus; the jumper should be moved to
right side to close the bus.
DEFAULT MODBUS END