8.1
Communication overview
Our series of VFDs provide users with a common industrial control RS485
communication interface, in which The MODBUS standard protocol is used for
communication. The VFDs can be used as slave connected to the host (such as
PLC controller, PC), both of which have the same communication interface and
protocol, for the purpose of centralized monitoring of the VFDs. Or one VFD can be
used as host and other VFDs as slaves, all connected with RS485 communication
interface, to achieve multi-machine interaction of the VFDs. And with this
communication interface, a Keyboard can also be connected to VFDs for remote
operation.
The MODBUS communication protocol of the VFD supports two transmitting ways:
RTU mode and ASCII, and either can be choose. The following is a detailed
description of the communication protocol of the VFD.
8.2
Communication protocol specification
8.2.1 Communications networking methods
（
1
）
networking methods with VFD as slave:
Fig.8-1 networking of slaves
PC as host
PLC as host
232-485
Conversion
RS485
Single host
Multi slaves
RS485
232-485
Conversion
PC as host
RS232
Single host
Multi slaves
VFD
VFD
VFD
VFD
VFD
8. Serial Port Communication Protocol of RS485
Larson Electronics, LLC
Phone:
Fax: (903) 498-3364
www.larsonelectronics.com
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