C.7 Message Format
YASKAWA ELECTRIC
TOEP C710656 10B YASKAWA Power Regenerative Unit - R1000 Instruction Manual
171
MEMOB
US/Modb
us
Commu
nica
tions
C
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.
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
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