Inovance Easy501 - RS485 Communication Instructions

‑36‑
Pin Signal Signal direction Description
1 TD+ Output Data transmission+
2 TD‑ Output Data transmission‑
3 RD+ Input Receive data (+)
4 ‑ ‑ Not used
5% ‑ ‑ Not used
6 RD‑ Input Receive data (‑)
7 ‑ ‑ Not used
08 ‑ ‑ Not used
Length requirement
The cable between devices cannot exceed 100 m when the EtherCAT bus is used,
exceeding of which may attenuate the signal and affect normal communication.
Technical requirements
Short circuit, open circuit, misalignment, or poor contact does not occur during 100%
continuity test. Cables compliant with the following specifications are recommended.
Item Specification
Cable type Flexible crossover cable, S‑FTP, Cat5e
Standards
compliance
EIA/TIA568A, EN50173, ISO/IEC11801
EIA/TI Abulletin TSB
EIA/TIA SB40‑A&TSB36
Cross sectional area
of the cable
26AWG
Cable category Twisted pair
Number of pairs 4
4.5 RS485 Communication Instructions
It is recommended to use a shielded twisted pair cable as the RS485 bus. Connect a
120 Ω termination resistor to both ends of the bus respectively to prevent signal
reflection. Connect the signal reference grounds of all nodes together. Up to 31 nodes
can be connected and the distance between nodes must be less than 3 m.
The RS485 bus topology is shown in the figure below.