YASKAWA OYMC V1000

2.8 Message Examples
YASKAWA ELECTRIC SIEP C710606 10A YASKAWA AC Drive - V1000 PRELIM. Programming Manual 273
MEMOBUS/Modbus Communications
2
◆ Loopback Test
Function code 08H performs a loopback test. This test returns a response message with
exactly the same content as the command message and can be used to check the
communications between the master and slave. User-defined test code and data values can
be set.
The following table shows a message example when performing a loopback test with the
slave 1 drive.
◆ Writing to Multiple Registers
Function code 10h allows the user to write multiple drive MEMOBUS/Modbus registers
with one message. This process works similar to reading registers, i.e., the address of the
first register that is to be written and the data quantity must be set in the command message.
The data to be written must be consecutive so that the register addresses are in order, starting
from the specified address in the command message. The data order must be high byte, then
lower byte.
The following table shows an example of a message where a forward operation has been set
with a frequency reference of 60.0 Hz for the slave 1 drive.
If parameter values are changed using the Write command, depending on the setting of H5-
11, an Enter command will be necessary to activate the data or save them. Refer to H5-11:
Communications Enter Function Selection on page 265 and Enter Command on page 289
for detailed descriptions.
Command Message Response Message (normal) Response Message (fault)
Slave Address 01H Slave Address 01H Slave Address 01H
Function Code 08H Function Code 08H Function Code 89H
Test Code
Upper 00H
Test Code
Upper 00H Error Code 01H
Lower 00H Lower 00H
CRC-16
Upper 86H
Data
Upper A5H
Data
Upper A5H Lower 50H
Lower 37H Lower 37H
CRC-16
Upper DAH
CRC-16
Upper DAH
Lower 8DH Lower 8DH
Command Message Response Message (normal) Response Message (fault)
Slave Address 01H Slave Address 01H Slave Address 01H