abc 2000 Series User Manual page 177

message and assume that the next byte is a new message the
address of the domain.likewise,
characters of time and than a massage before, receiving equipment
will think it is a continuation of the previous massage.This will result
in an error, because in the final CRC field value can't be right.
RTU fi"ame format:
The header START
frame
Slave address ADR
command code CMD
Date content DATA
Data content DATA
..
. . .
Data contentDATAO
highmorder position
CHK
low-order position of
CHK
END
CMD(Command instruction)and DATA(the description of data word)
command code:03H,read N word(Word)(Can read the most words
of 1 2)For example,From the machine address of 01 inverter startup
F105 continuous read for two consecutive values
The host command information
high-order position of the starting address
low-order
high-Order position of register
!ow-order
low-order position
high-order position of CRC CHK
In response to information from the slave machine
Set PD.05 to 0:
lowm0rder position of
Data high-order pos
Data low-order position of F002H
03:
(N-1 )
)
Information
-2
(N
address,
.
function code parameter values, etc
CRC
of
CRC
CMD
of
the startina
position of register
of CRC CHK
CMD
bytes
i t ion of
F002H
if
a new message in less than 3.5
characters
3.5
Communication address:
Read the machine parameters;
the machine parameters
content
function code number of parameters,
estimated value: CRC value
3.5 characters'time
address
Wait
to
· 1 72-
1-247
Function code parameter
01H
03H
F1H
05H
OOH
02H
calculate the CRC CHK
values
H
0
1
3 H
0
OOH
04H
OOH
OOH
write
06: