User`s manual

Message Communications Basic Format Chapter 7-3

Slave Address

• The Master can communicate with a maximum of 32 Slaves over RS-

422A/485. A unique Slave address is allocated to each Slave (Inverter) for

communications.

• Slave addresses are within a range from 00 to 32 (00 through 20 Hex). If a

DSR message is issued to Slave address 00, the message will be a

broadcast message.

Note The broadcast message is addressed to all Slaves. Only the RUN command

(register 0001 Hex) and frequency command (register 0002 Hex) can be

written to the message. The Inverter receiving this message does not return a

response regardless of whether or not the message is received properly.

Therefore, for measures against communications errors, the monitor function

of the Inverter should be used for checking the reception of broadcast

messages.

Function Code

• The function code is a command giving instructions of the details of

processing to the Inverter.

• The following three functions codes are available.

Note 1. Do not use any code other than the above, otherwise the Inverter will

detect a communications error and return an error message.

2. The Inverter uses the same function code for the response. If an error

occurs, however, the MSB of the function code will be set to 1. For

example, if an error occurs in a DSR message with function code 03, the

function code of the response will be 83.

Communications Data

Communications data is attached to the command. The contents and its

arrangement of communications data vary with the function code. For details,

refer to 7-4 DSR Message and Response.

Function code Command name Description

03 Hex Data read Reads the data of the specified register number. Consecutive data

of a maximum of 16 words (32 bytes) can be read.

08 Hex Loop-back test The DSR message is returned as a response. This command is

used for checking the status of communications.

10 Hex Data write The attached data in the format is written to the specified register

number. Consecutive data of a maximum of 16 words (32 bytes)

can be written.