C.7 message format, Message content, Slave address – Yaskawa R1000 Series Power Regenerative Unit User Manual

Page 184: Function code, Data, Error check

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184

YASKAWA ELECTRIC TOEP C710656 08B YASKAWA Power Regenerative Unit - R1000 Instruction Manual

C.7 Message Format

C.7 Message Format

Message Content

In MEMOBUS/Modbus communications, the master sends commands to the slave, and the slave responds. The message
format is configured for both sending and receiving as shown below, and the length of data packets depends on the
command (function) content.

Slave Address

The slave address in the message defines the note the message is sent to. Use addresses between 0 and FF (hex). If a
message with slave address 0 is sent (broadcast), the command from the master will be received by all slaves. The slaves
do not provide a response to a broadcast type message.

Function Code

The three types of function codes are shown in the table below.

Data

Configure consecutive data by combining the MEMOBUS/Modbus register address (test code in case of a loopback test)
and the data the register contains. The data length changes depending on the command details.

A regenerative unit MEMOBUS/Modbus register always has a data length of two bytes. Data written into regenerative
unit registers must also always have a length of two bytes. Register data read out from the regenerative unit will always
consist of two bytes.

Error Check

The regenerative unit uses a CRC-16 (cyclic redundancy check, checksum method) for checking data validity. Use the
procedure described below when calculating the CRC-16 checksum for command data or when verifying response data.

Function

Code

Function Name

Data Length (bytes)

Command Message

Response Message

Minimum

Maximum

Minimum

Maximum

03H

Read MEMOBUS/Modbus registers

8

8

7

37

08H

Loopback test

8

8

8

8

10H

Write to multiple MEMOBUS/Modbus
registers

11

41

8

8

SLAVE ADDRESS

FUNCTION CODE

DATA

ERROR CHECK

TOEP_C710656_08B_1_0.book 184 ページ 2015年2月5日 木曜日 午前10時7分

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