Unitronics UMI-B1 UL Series Operation Manual page 118

UMI-B1 UL Series Inverter
behind.
RTU slave response message (from the inverter to the master)
START
ADDR
CMD
Byte number
Data high bit of address 0004H
Data low bit of address 0004H
Data high bit of address 0005H
Data low bit of address 0005H
CRC CHK low bit
CRC CHK high bit
END
The meaning of the response is that:
ADDR = 01H means the command message is sent to the inverter with the address of
01H and ADDR occupies one byte
CMD=03H means the message is received from the inverter to the master for the
response of reading command and CMD occupies one byte
"Byte number" means all byte number from the byte (excluding the byte) to CRC byte
(excluding the byte). 04 means there are 4 byte of data from the "byte number" to "CRC
CHK low bit", which are "digital address 0004H high bit", "digital address 0004H low bit",
"digital address 0005H high bit" and "digital address 0005H low bit".
There are 2 bytes stored in one data with the fact that the high bit is in the front and the
low bit is in the behind of the message, the data of data address 0004H is 1388H, and
the data of data address 0005H is 0000H.
CRC occupies 2 bytes with the fact that the high bit is in the front and the low bit is in the
behind.
7.3.2 Command code: 06H
06H (correspond to binary 0000 0110), write one word (Word)
The command means that the master write data to the inverter and one command can
write one data other than multiple dates. The effect is to change the working mode of the
inverter.
For example, write 5000 (1388H) to 0004H from the inverter with the address of 02H,
the frame structure is as below:
RTU master command message (from the master to the inverter)
T1-T2-T3-T4
01H
03H
04H
13H
88H
00H
00H
7EH
9DH
T1-T2-T3-T4
116
Communication protocol