Goodrive100 inverters
Communication protocol
IKR Aandrijven en Besturen
www.ikr-industries.nl
digital bit right to the other device. The digital bit, even/odd checkout and end bit should be set as the same
in real application.
The Modbus minimum idle time between frames should be no less than 3.5 bytes. The network device is
detecting, even during the interval time, the network bus. When the first field (the address field) is received,
the corresponding device decodes next transmitting character. When the interval time is at least 3.5 byte,
the message ends.
The whole message frame in RTU mode is a continuous transmitting flow. If there is an interval time (more
than 1.5 bytes) before the completion of the frame, the receiving device will renew the uncompleted
message and suppose the next byte as the address field of the new message. As such, if the new message
follows the previous one within the interval time of 3.5 bytes, the receiving device will deal with it as the
same with the previous message. If these two phenomena all happen during the transmission, the CRC will
generate a fault message to respond to the sending devices.
The standard structure of RTU frame:
START
T1-T2-T3-T4(transmission time of 3.5 bytes)
ADDR
Communication address: 0~247(decimal system)(0 is the broadcast address)
CMD
03H:read slave parameters
06H:write slave parameters
DATA (N-1)
…
DATA (0)
The data of 2*N bytes are the main content of the communication as well as
the core of data exchanging
CRC CHK low bit
Detection value:CRC (16BIT
）
