RS-485 Communication Features
Error Response
• A request starts with ENQ and ends with EOT.
• A normal response starts with ACK and ends with EOT.
• An error response starts with NAK and ends with EOT.
• A station ID indicates the inverter number and is displayed as a two-byte ASCII-HEX string
that uses characters 0-9 and A-F.
• CMD: Uses uppercase characters (returns an IF error if lowercase characters are
encountered)—please refer to the following table.
‘R’ 52h Read
‘W’ 57h Write
‘X’ 58h Request monitor registration
‘Y; 59h Perform monitor registration
• Data: ASCII-HEX (for example, when the data value is 3000: 3000 → ‘0’’B’’B’’8’h → 30h 42h
42h 38h)
• Error code: ASCII-HEX (refer to 7.3.1.4 Error Code on page 240
)
• Transmission/reception buffer size: Transmission=39 bytes, Reception=44 bytes
• Monitor registration buffer: 8 Words
• SUM: Checks communication errors via sum.
SUM=a total of the lower 8 bits values for station ID, command and data (Station
ID+CMD+Data) in ASCII-HEX.
For example, a command to read 1 address from address 3000:
SUM=‘0’+‘1’+’R’+‘3’+‘0’+‘0’+‘0’+’1’ = 30h+31h+52h+33h+30h+30h+30h+31h = 1A7h (the
control value is not included: ENQ, ACK, NAK, etc.).
Broadcasting sends commands to all inverters connected to the network simultaneously. When
commands are sent from station ID 255, each inverter acts on the command regardless of the station
ID. However no response is issued for commands transmitted by broadcasting.
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