Omron J7 series, User Manual

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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.