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C
O
M
M
U
N
C I
T A
O I
N
S
G
U
D I
E
Modbus Functions
Function Code 01H
M
X
3
5
0
A
U
T
O
M
A
T
C I
T
R
A
N
S
E F
R
Modbus implementation: Read Input Status
MX350 implementation: Read Net Control Status
This function code is supported for a selective range of commands for MX350 for net
control functionality. This function reads the ON/OFF status for each net control
command. The query message specifies the starting command and number of commands
status to be read. Commands are addressed starting at zero.
The master/slave packets have the following format:
Table 1: MASTER/SLAVE PACKET FORMAT FOR FUNCTION CODE 03H
MASTER TRANSMISSION
SLAVE ADDRESS
FUNCTION CODE
STARTING ADDRESS
NUMBER OF POINTS
C
R
C
SLAVE RESPONSE
SLAVE ADDRESS
FUNCTION CODE
BYTE COUNT
D
A
A T
C
R
C
Each returned data bit is an ON/OFF status. The number of returned data bytes will
change according to the number of points requested.
The following table lists the supported command addresses for this function code:
C
O
N
T
R
O
L
S
S Y
E T
M
–
C
O
M
M
U
N
C I
BYTES
EXAMPLE
1
11
1
02
2
00 C4
2
00 02
1
BYTES
EXAMPLE
1
11
1
02
1
01
1
1
1
A
T
O I
N
S
G
U
D I
E
R
4 S
8
5
N I
E T
F R
A
C
E
M (
O
D
B
U
S
DESCRIPTION
message for slave 17
read net control status
starting command address
number of status bits
C
R
C
e
r r
r o
o c
d
e
DESCRIPTION
message from slave 17
read net control status
number of status bytes
b
t y
s e
f o
n
t e
o c
n
r t
l o
t s
t a
C
R
C
e
r r
r o
o c
d
e
T R
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5
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