GE Industrial Solutions EntelliPro ES - Manual (Page 138)

EP OS MOTOR MANAGEMENT SY STEM – INSTRUCTION MANUAL 4.1
CHAPTER 4: COMMUNICATION
GE Industrial Solutions
EPOS Motor Management System
Chapter 4: Communication
The EntelliPro DP offers two communication protocols: Modbus RTU and Profibus DP over RS-485. They are
independent and can run simultaneously.
4.1 Modbus RTU
Modbus is a master-slave protocol, which means that a single host or master device initiates and controls all
communication with the other devices on the network. The hardware interface is implemented as two-wire
RS-485. In a two-wire link, data are transmitted and received over the same lines. In such a half-duplex link, data
are transmitted and received in separate time slices. Also, per the EIA-485 standard, the number of devices that
can be connected on a single communication channel is limited to 32 (including the master).
Please refer to the EIA-485 standard for complete details of the physical interface including cabling, termination,
and shielding.
4.1.1 Modbus address setting
In a Modbus RTU Network, each EntelliPro ES module must have a unique address that can be set from 1 to 126.
Address 0 is the broadcast address detected by all IEDs in the serial link. Addresses do not have to be sequential,
but no two units can have the same address.
.
Generally, each unit added to the link uses the next higher address, starting at 1. The Modbus slave address can be set
using the front-panel switches or using software. Figure 9-1 shows the switch setting and Modbus terminal
connection.
The Modbus slave address configuration (front switches-hardware or software) can be done In WinESG
parameterization/Modbus setting panel shown In Illustration below or Modbus function code 6 register 102.