Rs485 Port - Logic IO RTCU LX2 pro Technical Manual

RTCU LX2 pro Technical Manual V1.00
Advanced Automotive M2M/IoT Gateway

RS485 Port

RS485 is a multi-drop network with a maximum of 32 nodes connected simultaneously to the bus.
Each RS485 bus contains an RSA, an RSB signal, and a signal ground, which must always be
connected to the common signal ground for all nodes connected to the RS485 bus!
The maximum cable length for the RS485 bus is according to the EIA/TIA-485-A standard (max.
1000m @ <100kbit); this limit is highly influenced by the quality of the cable, signaling rate, noise etc.
At longer cable lengths, noisy environments, or high communication speeds, it might be necessary to
terminate the transmission line with a 120
terminate it and avoid signal reflections. If the RTCU LX2 pro is used as an endpoint node, the RS485
communication lines can be terminated with 120Ω by using configuration DIP-switch 4, located on
the front, behind the end-cap. By default, the RS485 communication lines are not terminated.
Please note: For best performance, protection, and noise immunity, it is advised to use a shielded
cable to connect the device to the RS485 communications bus.
X2: 12 pin COM connector overview
Pin Name
5 RS485A
6 RS485B
11 GND
1 Assuming use of a CAT5 twisted pair cable
Logic IO ApS.
Holmboes Allé 14
8700 Horsens
Denmark
ohm resistor at each end of the transmission line to
1
Description
RS485 non-inverting signal (A)
RS485 inverting signal (B)
Signal Ground
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