Communication Protocol - IMO VXSM75-1 Instruction Manual

9-4-4 Communication Protocol

(1) Serial communication specification
Physical level
Number of connected
stations
Transmission speed
Synchronization method
Transmission method
Transmission protocol
Character type
Character length
Transmission distance
Stop bit
Frame length
Parity
Error check method
Table 9-4-3 Serial communication specification
(2) Transmission protocol
It is the half duplex communication in the
polling/selecting method. The inverter always
waits for a write request (selecting) or a read
request (polling) from the host. The inverter,
when receiving in the wait state a request frame
to the own station from the host, returns a
response frame. Upon polling, it returns data
together. In the case of broadcasting (selection
of all stations in a batch), no response is
returned.
• Polling/selecting
Response internal time+ (0~10ms)
• Broadcast
9-13
Compliance with EIA RS-485 (2-wire type)
Host x 1 unit, inverter x 31 units (Station address 1 to 31)
19200, 9600, 4800, 2400, 1200[bit/s]
Start-stop
Half duplex
Polling/selecting, broadcast
ASCII 7 bits
Selection between 7 and 8 bits
Max. 500 m
Selection between 1 and 2 bits
Standard frame: fixed to 16 bytes, short frame: 8 or 12 bytes
Selection from none, even and odd
Checksum, parity, framing error
10 msec or longer
Specifications