Triconex Trident - Modbus Serial Cables

RS-485 Modbus Serial Cables 215
Appendix A Pin-Outs for Cables and Connectors
RS-485 Modbus Serial Cables
RS-485 Modbus serial cables are used for point-to-point and multi-point
connections between an MP or CM and a Modbus master.
The first figure below shows a point-to-point connection between a Modbus master
and one slave only. The second figure shows a multi-point connection which
includes one Modbus master and 2 to 32 slaves.
The MP and CM serial ports are configurable for multi-point RS-485 operation
without using modems. The following table shows the RS-485 network
specifications.
The network trunk should consist of double twisted-pair wires. When the trunk
consists of double twisted pairs, one pair serves as the output line for the Modbus
master (input line to all slaves). The other pair serves as the input line to the
Modbus master (output line from all slaves). When the trunk consists of a single
twisted pair, it serves as both the output and input lines to the Modbus master and
all slaves. The trunk accommodates up to 32 two-foot branches, without restriction
Point-to-Point
Connection
Modbus
Master
Slave
Multi-Point
Connection
Modbus
Master
~
Branch
Trunk
Branch Branch
Slave Slave Slave
Item Specification
Nodes One Modbus master and one slave
Cable length Cable dependent—1.2 km (4000 ft) maximum using
24-AWG twisted-pair wire (shielding recommended)
Transmission
rate (bps)
1200, 2400, 4800, 9600, 19.2 K, 38.4 K, 57.6 K, 115.2 K