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4.2.2.5 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
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
