Fuji Electric FRENIC MEGA G2 Series - Common Specifications

9.1 Overview of RS-485 Communication
9-2
9.1.1 RS-485 common specifications
Table 9.1-1
Item
Specification
Protocol
FGI-BUS
Modbus RTU
Compliance
Fuji general-purpose inverter
protocol
Modicon Modbus RTU-compliant
(only in RTU mode)
Connection quantity
Host device: 1, Inverters: Up to 31
Electrical specification
EIA RS-485
Connection to RS-485
RJ-45 connector or terminal block
Synchronization
Start-stop synchronization
Communication system
Half-duplex
Baud rate (bps)
2400, 4800, 9600, 19200, 38400, 57600, 76800 and 115200 bps
Max. transmission cable
length
500 m (1640 ft)
Station No.
1 to 31
1 to 247
Message frame format
FGI-BUS
Modbus RTU
Frame synchronization
Header character detection (SOH)
Detection of no-data time
(for 3 characters period)
Frame length
Standard transmission: 16 bytes
(fixed)
High-speed transmission: 8 or 12
bytes
Variable length
Max. transfer data
Write: 1 words
Read: 1 words
Write: 100 words
Read: 100 words
Messaging system
Polling/selecting/broadcast
Transmission character
format
ASCII
Binary
Character length
8 or 7 bits
Selectable with function code
8 bit (fixed)
Parity
Even, Odd, or None (selectable with function code)
Stop bit length
1 or 2 bits
Selectable with function code
No parity: 2 bits/1 bit
Parity: 1 bit
Select by parity setting.
Error checking
Check sum
CRC-16