MF5700
User
Manual
25
|
P a g e
5.6.3
Frame
The
frame
function
is
based
on
the
standard
Modbus
RTU
framing:
Start_bits
Address
Function
codes
Data
CRC
Stop_bits
T1
‐
T2
‐
T3
‐
T4
8
bit
8
bit
N
8
bit
(20
≥
n
≥
0)
16
bit
T1
‐
T2
‐
T3
‐
T4
Start_bits
:
4
periods
bit
time,
for
a
new
frame.
Address:
The address can be set from 1 to 255 except for 157 (0x9d). 0 is the broadcast address.
Function codes:
Define the product (MF5700)'s functions/actions (slaves), either execution or response.
Data:
The address of the register, length of data, and the data themselves.
CRC:
CRC verification code. The low byte is followed by the high byte. For example, a 16 bit
CRC is divided into BYTE_H and BYTE_L. In the framing, the BYTE_L will come first, then
followed by the BYTE_H. The last one is the STOP signal.
Stop_bits:
4 periods bit time, for ending the current frame.
5.6.4
Function
codes
The
Modbus
function
codes
applied
for
the
product
are
the
sub
‐
class
of
the
standard
Modbus
function
codes.
These
codes
are
used
to
set
or
read
the
registers
of
the
product:
Code
Name
Functions
0x03
Read
register
Read
register(s)
0x06
Set
single
register
Write
one
single
16
‐
bit
register
0x10
Set
multiple
registers
Write
multiple
registers
5.6.5
Registers
The
product
(MF5700)
has
multiple
registers
available
for
the
assignment
of
the
various
functions.
With
these
functions,
the
user
can
obtain
the
data
from
the
products,
such
as
product
address
and
flow
rates
from
the
registers,
or
set
the
product
functions
by
writing
the
corresponding
parameters.
The
currently
available
registers
are
listed
in
the
following
table,
and
the
registers
may
be
customized
upon
contacting
the
manufacturer.
Where
R:
read;
W:
write
‐
only;
W/R:
read
and
write.
Note:
At
the
time
of
shipping,
the
write
protection
function
is
enabled
except
for
address
and
baud
rate.
Once
the
user
completes
the
register
value
change,
the
write
protection
will
be
automatically
enabled
once
again
to
prevent
incidental
data
loss.
