Yaskawa GPD 515-G5 Modbus RTU - Manual (Page 25)

The Message Format 6-5
Normal Response Message
The normal response message contains the same slave address and function code as the
command message, indicating to the master which slave is responding and to what type of
function it is responding.
The number of data bytes is the number of data bytes returned in the response message. The
number of data bytes is actually the quantity (in the command message) times 2, since there are
two bytes of data in each register.
The data section of the response message contains 8 upper and 8 lower bits of data for each
register that has been read from the drive.
A CRC-16 value is generated from a calculation using the values of the address, function code,
number of data bytes, and register data sections of the message. The procedure for calculating a
CRC-16 value is described at the end of this chapter. How the response message is handled by
the master depends on what master is used. When the master receives the response message it
should calculate a CRC-16 value and compare it to the one in the CRC-16 field of the response
message. If these two CRC-16 values are the same the master has received the proper
response message.
The starting register, 20h
(Frequency Reference),
has a value of 1770h or
6000 dec. (60.00 Hz)
02h
SLAVE ADDRESS
FUNCTION CODE
03h
17h
70h
START-
ING
REGISTER
CONTENTS UPPER
LOWER
NO. OF DATA BYTES
08h
NEXT
REGISTER
CONTENTS
17h
70h
UPPER
LOWER
NEXT
REGISTER
CONTENTS
01h
09h
UPPER
LOWER
NEXT
REGISTER
CONTENTS
00h
00h
UPPER
LOWER
CRC-16
38h
AC h
LOWER
UPPER
The next register, 21h
(Output Frequency), has
a value of 1770h or 6000
dec. (60.00 Hz).
The next register, 22h
(Output Current), has a
value of 109h or 265 dec.
(drive rating / 8192).
The next register, 23h
(Control Method), has a
value of 00h or 0 dec.
(V/f Control).