C.8 Message Examples; Reading Drive Memobus/Modbus Register Contents; Loopback Test; Writing To Multiple Registers - YASKAWA A1000 Series Technical Manual

C.8 Message Examples

Below are some examples of command and response messages.

◆ Reading Drive MEMOBUS/Modbus Register Contents

Using the function code 03H (Read), a maximum of 16 MEMOBUS/Modbus registers can be read out at a time.
The following table shows message examples when reading status signals, error details, data link status, and frequency
references from the slave 2 drive.
Command Message
Slave Address
Function Code
Upper
Starting No.
Lower
Upper
Data Quantity
Lower
Upper
CRC-16
Lower

◆ 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 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.
Command Message
Slave Address
Function Code
Upper
Test Code
Lower
Upper
Data
Lower
Upper
CRC-16
Lower

◆ 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.
and Refer to Enter Command on page 503
Command Message
Slave Address
Function Code
YASKAWA ELECTRIC SIEP C710616 27C YASKAWA AC Drive A1000 Technical Manual
Response Message (normal)
02H Slave Address
03H Function Code
00H Data Quantity
20H
1st storage register
00H
04H
Next storage
register
45H
F0H
Next storage
register
Next storage
register
CRC-16
Response Message (normal)
01H Slave Address
08H Function Code
00H
Test Code
00H
A5H
Data
37H
DAH
CRC-16
8DH
Refer to H5-11: Communications Enter Function Selection on page 483
for detailed descriptions.
Response Message (normal)
01H Slave Address
10H Function Code
02H
03H
08H
Upper 00H
Lower 65H
Upper 00H
Lower 00H
Upper 00H
Lower 00H
Upper 01H
Lower F4H
Upper AFH
Lower 82H
01H Slave Address
08H Function Code
Upper 00H Error Code
Lower 00H
CRC-16
Upper A5H
Lower 37H
Upper DAH
Lower 8DH
01H Slave Address
10H Function Code
C.8 Message Examples
Response Message (fault)
Slave Address
Function Code
Error Code
Upper
CRC-16
Lower
Response Message (fault)
Upper
Lower
Response Message (fault)
02H
83H
03H
F1H
31H
01H
89H
01H
86H
50H
01H
90H
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