Check code:
ASCII mode
：
Double byte ASCII code
Calculation method:
For message sending end, the calculation of LRC is the method of continuous
accumulation the byte from "slave address" to "running data" which is not
converted to ASCII code, discarding carry-over, reversing the 8 bit data, then plus
1 ( converting to complement), finally converted to ASCII code, putting into the
checkout area, high byte in front, low byte in post. For The message receiving end,
the same LRC method is used to calculating checksum of received data, and
comparing it with the received checksum. If they are equal, the message received
is correct. If not equal, the received message is wrong. If error, the message frame
is discarded with no answering, while the end continuing to receive the next frame
data.
RTU mode
：
two bytes of 16 hex
The CRC domain is two bytes, including a binary value of 16 bits. It is calculated
and added to the message by the sending end; while low byte added in front, and
high byte added in post then, so the high byte of CRC is the last of the message.
The receiving device re-calculates the CRC of the message, and compares it with
the CRC in receiving domain, if the two values are different, it means there is error
in received message, and the message frame is discarded, while there is no
responding but waiting for the next frame data. CRC checksum calculation method
reference to MODBUS protocol specification.
Communication protocol parameter definition:
definition
Parameter address
Function description
Commands
to VFD
（
06H）
2000H
0001H
：
RUN
0002H
：
FWD
0003H
：
REV
0004H
：
JOG
0005H
：
FWD JOG
0006H
：
REV JOG
0007H
：
DEC and STOP
0008H
：
STOP
0009H
：
JOG STOP
000AH
：
RESET
2001H
Freq. setting
Larson Electronics, LLC
Phone:
Fax: (903) 498-3364
www.larsonelectronics.com
49
of
52
VFD-1P-220.240-1HP-7A-DCM
(877) 348-9680