VFD68 Variable Frequency Drives
96
Message Format Types
Read Holding Register Data (H03 or 03)
Can read the description of the following items:
1.
system environment variables
2.
real-time monitor
3.
fault history
4.
VFD parameters assigned to the holding register area
Table 91: Query Message
Slave
Address
Function
Starting Address
Number of Points
CRC Check
(8 bit)
H03 (8 bit)
H (8 bit)
L (8 bit)
H (8 bit)
L (8 bit)
L (8 bit)
H (8 bit)
Table 92: Normal Response Message
Slave
Address
Function
Byte
Count
Data
CRC Check
(8 bit)
H03 (8 bit)
(8 bit)
H (8 bit)
L (8 bit)
...
(n x 16 bit)
L (8 bit)
H (8 bit)
Table 93: Query Message Description
Message
Description
Slave Address
Address to which the message is sent. Broadcast communication cannot be made (0 is invalid).
Function
Set H03
Starting Address
Set the address at which holding register data read is started
Starting address = starting register address (decimal)-40001
For example, setting the starting address 0001 reads the data of the holding register 40002.
Number of Points
Number of holding registers from which the data is read (125 maximum).
Table 94: Normal Response Message Description
Message
Description
Byte Count
The setting range is H02 to H14 (2 to 20). The byte count is set at twice the number of points.
Data: Read Data
The number of data to be read equals the number of points. Data are read in order of high byte
and low byte, and set in order of starting address data, starting 1 data, starting address
+2 data, and so forth.
