User manual

69
For the CS121 there is normally no difference between these two functions.
Query:
slave no function code address of first word
to read
word count Checksum
LRC or CRC
1 byte 1 byte High byte Low byte High byte Low byte 1 or 2 byte(s)
Answer:
slave no function code Byte count high byte
of first
word
low byte of
first word
bytes with
contents of n
words
Checksum
LRC or CRC
1 byte 1 byte 1 byte 1 byte 1 byte n * 2 bytes 1 or 2 byte(s)
Example: Read Words, Function 04h, ASCII Mode
Read one word at address 63h (= 99 decimal):
Query:
Byte 1 2, 3 4, 5 6, 7 8, 9 10, 11 12, 13 14, 15 16 17
address of first
word to read
word count to
read
Mea-
ning
Lead-
ing
colon
Slave
num-
ber
Func-
tion
code
high
byte
low
byte
high
byte
low
byte
LRC Carria
ge
return
line
feed
LF
ASCII : 0 1 0 4 0 0 6 3 0 0 0 1 9 7 <CR> <LF>
HEX [3A] [30][31] [30][34] [30][30] [36][33] [30][30] [30][31] [39][37] [0D] [0A]
Answer:
Byte 1 2, 3 4, 5 6, 7 8, 9 10, 11 12, 13 14 15
Mea-
ning
leadin
g
colon
Slave
number
function
code
byte
count
content
s of the
word
LRC carriag
e return
line
feed
LF
high
byte
low
byte
ASCII : 0 1 0 4 0 2 1 2 3 4 B 3 <CR> <LF>
HEX [3A] [30][31] [30][34] [30][32] [31][32] [33][34] [42][33] [0D] [0A]
ASCII: Data, which will send over the link as ASCII characters.
HEX: Hexadecimal values of the data
Æ The word at address contains the value 1234h = 4660 decimal.
Example: Read Words, Function 04h, RTU Mode
Read one word at address 63h (= 99 decimal):
Query:
Byte 1 2 3 4 5 6 7 8
address of first
word to read
word count to
read
CRC Meani
ng
silent
interval
>= 3.5
charact
ers
Slave
number
function
code
high
byte
low
byte
high
byte
low
byte
low
byte
High
byte
silent
interval
>= 3.5
charact
ers
RTU
HEX
[01] [04] [00] [63] [00] [01] [C1] [D4]
Answer:
Byte 1 2 3 4 5 6 7
Meani
silent
Slave function byte Content CRC Silent