User manual

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● Please use a soft enough dry cloth or other alternatives to wipe internal and external surface.
● If dirt is serious, user can use a mild detergent. Any senior furniture cleaning products can be
used to clean the under cover.
Appendix Ⅲ Common Knowledge on RS-485 Bus
1. Basic Feature of RS-485bus
According to industry bus standard of RS-485, RS-485 bus is half-duplex communication bus
with the characteristic impedance of 120Ω, whose maximum load capacity is 32 payloads
(including the master device and the controlled device).
2. Mode of Connection and Terminal Resistance
2.1 Industry standard of RS485 bus requires that connection mode in a daisy chain should be
used between the devices with 120Ω terminal resistances connected at the both ends.
As shown in fig. 26 and fig. 27 is simplified connection, but the distance of part "D" shall not
beyond 7 meters.
Fig 26 Fig 27
2.2 120Ω terminal resistance is connected as shown in fig 27.
120Ω terminal resistance is available in the circuit board, which is on the power board below the
mounting bracket.
When connecting 120Ω resistance if needed, just take the mini jumper from "OFF" to "ON".
Then the 120Ω resistance is connected to the circuit. The factory default of mini jumper is in
"OFF" position.