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CHAPTER 8 - CFW-09 OPTIONS AND ACCESSORIES
Writing Telegram
This telegram sends data to the inverters variables. The inverter answers by
indicating if the data have been accepted or not.
Format of the writing telegram:
EOT:
control character of End Of Transmission;
ADR:
inverter address;
STX:
control character of Start of TeXt;
TEXT:
consists in:
CODE:
variable address;
“ =”:
separation character;
VAL:
4 HEXADECIMAL digit value;
ETX:
control character of End of TeXt;
BCC:
Byte of CheCksum - EXCLUSIVE OR of all the bytes between STX
(excluded) and ETX (included).
Format of the inverter answer telegram:
Acceptance:
ADR:
inverter address;
ACK:
ACKnowledge control character;
No acceptance
:
ADR:
inverter address;
NAK:
Not AcKnowledge control character.
That means that the data were not accepted and the addressed variable
continues with its old value.
The inverters and the master test the telegram syntax.
The answers for the respective verified conditions are defined as follows:
Reading telegram:
No answer: with wrong telegram structure, control characters received
incorrectly or wrong inverter address;
NAK: CODE corresponding to the variable does not exist or there is only
writing variable;
TEXT: with valid telegrams.
8.13.3.5
Execution and
Telegram Test
1) Master:
2) Inverter:
ADR NAK
ADR ACK
or
CODE
VAL
(Hexadecimal)
TEXT
EOT
ADR
STX
=
xH
xH
xH
xH
ETX
BCC
