Hitachi WJ200-001S - Appendix B: Modbus Network Communications; Introduction

B2
Introduction
WJ200 Series inverters have built-in RS-485 serial communications, featuring the
Modbus RTU protocol. The inverters can connect directly to existing factory networks
or work with new networked applications, without any extra interface equipment. The
specifications are in the following table.
Item
Specifications
User-selectable
Transmission speed
2400 / 4800 / 9600 / 19.2k / 38.4k /
57.6k / 76.8k / 115.2k bps

Communication mode
Asynchronous

Character code
Binary

LSB placement
Transmits LSB first

Electrical interface
RS-485 differential transceiver

Data bits
8-bit (Modbus RTU mode)

Parity
None / even / odd

Stop bits
1 or 2 bits

Startup convention
One-way start from host device

Wait time for response
0 to 1000 msec.

Connections
Station address numbers from 1 to 32

Connector
Terminal connector

Error check
Overrun, Framing block check code,
CRC-16, or horizontal parity

Cable length
500m maximum
The network diagram below shows a series of inverters communicating with a host
computer. Each inverter must have a unique address, from 1 to 32, on the network. In
a typical application, a host computer or controller is the master and each of the
inverter(s) or other devices is a slave.
1
2
31