WEG CFW-09 User Manual page 303

CHAPTER 8 - CFW-09 OPTIONS AND ACCESSORIES
304
READING TELEGRAM: for inquiring of the inverter variable content;
WRITING TELEGRAM: to change inverter variable content or to send
controls to the inverters.
NOTE!
No transmission between two inverters is possible. The master has the bus
access control.
Reading Telegram
This telegram allows the master receive from the inverter the content
corresponding to the inquiry code. In the answer telegram the inverter transmits
the data requested by the master.
1) Master:
EOT ADR
2) Inverter:
ADR STX
Format of the reading telegram:
EOT: control character of End of Transmission;
ADR: inverter address (ASCII@, A, B, C, to ) (ADdRess);
CODE: address of the 5-digit variable coded in ASCII;
ENQ: control character ENQuiry (enquiry).
Format of the inverter answer telegram:
ADR: 1 character - inverter address;
STX: control character - Start of TeXt;
TEXT: consists in:
CODE: address of the variable;
"=": separation of character;
VAL: 4 digits value (HEXADECIMAL);
ETX: control character - End of TeXt;
BCC: CheCksum Byte- EXCLUSIVE OR of all the bytes between STX
(excluded) and ETX (included).
NOTE!
In some cases there can be an inverter answer with:
ENQ
CODE
=
CODE
TEXT
ADR NAK refer to item 8.13.3.5
xH xH xH xH ETX
VAL
(Hexadecimal)
BCC