Inexpensive Ethernet cables (Cat 5, Cat 5e, and Cat 6) can, and are often, used for many short RS-485 networks. The typical capacitance of 15 pF/ft and a characteristic impedance of 100 ohms meet the electrical requirements for RS-485 cables, although impedances closer to 120 ohm are preferable for better matching.

For MODBUS communications, a shielded and twisted pair cable is used. One example of such cable is Belden 3105A or as per EN:50290-2-23, IEC:60502. But any cable with similar characteristics can be used to connect all the devices together.

You can interface quickly and easily with most existing plant control architectures by using Belden Modbus Cables. Multiple options are available for a flexible, dependable Modbus solution.

Designed to meet both TIA RS-485 standards, and Modbus cable standards, HY-TREX® RS-485 Communication cable is an ideal choice for RS-485/Modbus RTU communication systems. The use of very fine stranding extends cable life and improves cable performance in …

2024年12月18日 · The main cable must be no longer than 700 m! This distance does not include the branches (which must nevertheless be short). The maximum number of devices that can be connected to a main cable is 32, including the Master.

2018年9月6日 · The Modbus RTU is a standard RS-485 network and you can use the same networking rules as per the Infinet network. As long as the baud rates are set the same you can even use an Infilink 200 or a B Link to act as a repeater.

Developed by Modicon, Modbus provides a master/slave communication between intelligent automation devices. Based on Belden 9841, the Modbus cable has an increased jacket thickness to ensure a correct termination into the Modbus connectors. CPR-Compliant options are available for this cable and are indicated in the product table.

Under ideal conditions, cable lengths of 4000 ft. (~1200 m) or more are possible. However, the cable recommended for long lengths can be expensive, so if there is an existing Ethernet infrastructure in place it may be more affordable to convert from BACnet MS/TP or Modbus RTU over RS-485 to BACnet TCP/IP or Modbus TCP/IP over Ethernet.

Connect the RS-485 cable to the dedicated terminals of the EKD controller: • Negative (B-) polarity wire to terminal 9 • Positive (A+) polarity wire to terminal 10

Proper termination, correct wiring connections, adequate grounding, suitable cable types, and appropriate cable length and routing are all crucial factors for a successful Modbus RTU RS485 installation.