Protocol; Reading Message - WEG CFW08 Vector inverter User Manual

8.19.3.4 Protocol

8.19.3.4.1 Reading Message

1) Master:
EOT ADDR
2) Inverter:
ADDR
3) Master:
EOT
CFW-08 OPTIONS AND ACCESSORIES
START B1
Start
bit
The transmission protocol meets the Standard ISO 1745 for the
transmission in code.
Only text character sequences without headers are used. The error/
fault monitoring is made through transmission related to the parity of the
individual 7 bit characters, according to ISO 646. The parity monitoring
is made according to DIN 66219 (even parity). The master uses two
types of messages:
READING MESSAGE: for inquiring of the inverter variable content;
WRITING MESSAGE: to change the inveter variable content or to
send comands to the inverters.
NOTE:
No transmission between two inverters is possible.
The master has the bus access control.
This message allows the master receive from the inverter the content that
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.
CODE
STX
CODE
Format of the reading message:
EOT: control character of End Of Transmission;
ADR: inverter address (ASCII@, A, B, C, ...) (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;
B2 B3 B4 B5
8 bits of information
ENQ
=
VAL
TEXT
B6 B7 B8 STOP
Stop
bit
ETX BCC
137