User`s guide

178
CHAPTER 8 - CFW-08 OPTIONS AND ACCESSORIES
Reading message:
for inquiring of the inverter variable
content;
Writing message:
to change the inverter variable content
or to send comands to the inverters.
Note:
No transmission between two inverters is possible.
The master has the bus access control.
Reading message:
This message allows the master to receive from the inverter
the content corresponding to the inquiry code. In the answer
message, the inverter transmits the data requested by the
master and it finishes the transmission with EOT.
2)Inverter:
ADR STX
= xH xH xH xH ETX BCC
CODE
VAL
(HEXADECIMAL)
TEXT
EOT ADR
ENQ
CODE
Format of the reading message:
EOT:
control character of End Of Transmission;
ADR:
inverter address (ASCII@,A, B, C, a ) (ADdRess);
CODE:
address of the 5-digit variable coded in ASCII;
ENQ:
control character ENQuiry(enquiry).
Format of the inverter answer message:
ADR:
1 character - inverter address;
STX:
control character - Start of TeXt;
TEXT:
consists in:
CODE:
address of the variable;
“ = “:
separation character;
VAL:
4 digits value HEXADECIMAL;
ETX:
control character - End of Text;
BCC:
CheCksum Byte - EXCLUSIVE OR of all bytesbetween
STX (excluded) and ETX (included).
NOTE
!
In some cases there can be an inverter answer with:
3) Master:
EOT
1) Master: