Fuji Electric FRENIC-Ace series, User Manual

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9.1 Overview of RS-485 Communication
9-2
9.1.1 RS-485 common specifications
Item Specifications
Protocol FGI-BUS Modbus RTU FRENIC Loader
(support only for standard)
Compliance Fuji general-purpose
inverter protocol
Modicon Modbus
RTU-compliant
(only in RTU mode)
Dedicated protocol
(Not disclosed)
Connection quantity Host device: 1, Inverters: Up to 31
Electrical mode EIA RS-485
Connection to RS-485 RJ-45 connector or terminal block
Synchronization
Asynchronous
Communication
system
Half-duplex
Transmission speed
(bps)
2400, 4800, 9600, 19200 and 38400 bps
Max. transmission
cable length
500 m (1640 ft)
Station No. 1 to 31 1 to 247 1 to 255
Message frame format FGI-BUS Modbus RTU FRENIC Loader
Frame
synchronization
Header character
detection (SOH)
Detection of no-data time
(for 3 characters period)
Header character
detection (Start code: 96
H
)
Frame length Normal transmission:
16 bytes (fixed)
High-speed transmission:
8 or 12 bytes
Variable length Variable length
Max. transfer data Write: 1 word
Read: 1 word Write: 100 words
Read: 100 words Write: 41 words
Read: 41 words
Messaging system Polling/Selecting/Broadcast Command message
Transmission
character format
ASCII Binary Binary
Character length 8 or 7 bit
Selectable with the
function code
8 bits (fixed) 8 bits (fixed)
Parity Even, Odd, or None (selectable by the function code) Even (fixed)
Stop bit length 1 or 2 bit
Selectable with the
function code
Parity none: 2/1 bit
Parity: 1 bit
Select by parity setting. 1 bits (fixed)
Error checking Sum-check CRC-16 Sum-check