Table of Contents
Advertisement
Goodrive390L Series Lift-Dedicated VFD
This chapter describes the communication protocol of the VFD.
7.1 Modbus protocol
The VFD provides RS485 communication interfaces and adopts the master-slave
communication based on the international standard Modbus communication protocol.
You can implement centralized control (setting commands for controlling the VFD,
modifying the running frequency and related function code parameters, and monitoring
the working state and fault information of the VFD) through PC/PLC, upper control
computer, or other devices to meet specific application requirements.
Modbus is a communication protocol for use with electronic controllers. By using this
protocol, a controller can communicate with other devices through transmission lines. It
is a general industrial standard. With this standard, control devices produced by different
manufacturers can be connected to form an industrial network and be monitored in a
centralized way.
The Modbus protocol provides two transmission modes, namely American Standard
Code for Information Interchange (ASCII) and remote terminal units (RTU). On one
Modbus network, all the device transmission modes, baud rates, data bits, check bits,
end bits, and other basic parameters must be set consistently.
A Modbus network is a control network with one master and multiple slaves, that is, on
one Modbus network, there is only one device serving as the master, and other devices
are the slaves. The master can communicate with any single slave or with all slaves. For
separate access commands, a slave needs to return a response. For broadcasted
information, slaves do not need to return responses.
7.1.1 Application of Modbus
The VFD uses the Modbus RTU mode and communicates through RS485 interfaces.
7.1.1.1 RS485
RS485 interfaces work in half-duplex mode and transmit data signals in the differential
transmission way, which is also referred to as balanced transmission. An RS485 interface
uses a twisted pair, where one wire is defined as A (+), and the other B (-). Generally, if the
positive electrical level between the transmission drives A and B ranges from +2V to +6V,
the logic is "1"; and if it ranges from -2V to -6V, the logic is "0".
On the VFD terminal block, the 485+ terminal corresponds to A, and 485- corresponds to
B.
202403 (V1.0）
7 Communication protocol
Communication protocol
56
Advertisement
Table of Contents
Need help?
Do you have a question about the Goodrive390L Series and is the answer not in the manual?
Questions and answers