LSIS G100, Operation Manual

Page: 229 / 343

Request
ENQ Station ID CMD Data SUM EOT
1 byte 2 bytes 1 byte n bytes 2 bytes 1 byte
Normal Response
ACK Station ID CMD Data SUM EOT
1 byte 2 bytes 1 byte n x 4 bytes 2 bytes 1 byte
Error Response
NAK Station ID CMD Error Code SUM EOT
1 byte 2 bytes 1 byte 2 bytes 2 bytes 1 byte
•
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. ASCII-HEX is a hexadecimal
notation composed of numbers between 0
–9 and letters between A–F.
•
CMD: Uses uppercase characters (returns an IF error if lowercase characters are
encountered)
—please refer to the following table.
Character ASCII-HEX Command
‘R’
52h Read
‘W’
57h Write
‘X’
58h Request monitor registration
‘Y’
59h Perform monitor registration
•
Data will be displayed as ASCII-HEX. (For example, if 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 220 )
•
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 error code
(Station ID+CMD+error code) in ASCII-HEX.
For example, a read request to read 1 address from address 3000 is
SUM=‘0’+‘1’+’R’+‘3’+‘0’+‘0’+‘0’+’1’ = 30h+31h+52h+33h+30h+30h+30h+31h = 1
A7h. When calculating SUM, the control value like ENQ, ACK, and NAK are not
included. Since SUM takes a lower byte, A7h becomes SUM.