YASKAWA ELECTRIC SIEP C710606 10A YASKAWA AC Drive - V1000 PRELIM. Programming Manual 269
2.7 Message Format
MEMOBUS/Modbus
Communications
2
2.7 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 20H. 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.
SLAVE ADDRESS
FUNCTION CODE
DATA
ERROR CHECK
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
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