How to Wire RS485 Bus for Anti-Interference? Standards and Key Points Checklist

RS485 bus is widely used in the field of industrial Internet of Things due to its strong anti-interference ability and long transmission distance. However, proper wiring is crucial for anti-interference. The following is a checklist of RS485 bus wiring standards and key points.

RS485 Bus Wiring Standards

Twisted Pair Wire: Use twisted pair wire as the transmission line to reduce electromagnetic interference.
Shielded Cable: Use shielded cable where possible and ensure that the shield layer is properly grounded.
Termination Resistance: Install termination resistors at both ends of the bus to reduce signal reflection.
Grounding: Ensure that all devices have good grounding to reduce common-mode interference.

Key Points Checklist

Use RS485 modules that comply with the EIA/TIA-485 standard.
Ensure that the number of devices on the RS485 bus does not exceed 32.
The bus length should not exceed 1200m, and a repeater should be considered for long-distance transmission.
Use the industrial-grade U485 USB/Bluetooth to RS485 module, which provides isolation and anti-interference functions.

Common Questions

Question?

What is the termination resistance of the RS485 bus?

Question?

Why does the RS485 bus need shielded cable?

Question?

How to choose the appropriate RS485 module?