WEG CFW-09 - Page 303

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CHAPTER 8 - CFW-09 OPTIONS AND ACCESSORIES
READING TELEGRAM:
for inquiring of theinverter 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.
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 inASCII;
ENQ:
controlcharacter ENQuiry(enquiry).
Format of the inverter answer telegram:
ADR:
1 character - inverter address;
STX:
control character - Start of TeXt;
TEXT:
consists in:
CODE:
addressof 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:
ADR
NAK
refer to item 8.13.3.5
Reading Telegram
This telegram allows the master receive from the inverter the content
corresponding to the inquirycode.In the answer telegram the invertertransmits
the data requested by the master.
2) Inverter:
ADR
STX
=
xH
xH
xH
xH
ETX
BCC
CODE
VAL
(Hexadecimal)
TEXT
EOT
ADR
ENQ
CODE
1) Master: