Loopback Test - Function Code 08; Loopback Test Query; Loopback Test Response; Write Multiple Coils - Function Code 15 - ABB COMMANDER 310 Operating Manual
Universal process controller modbus (rtu) communications option
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Also See for COMMANDER 310:
- Installation manual (24 pages) ,
- Programming manual (56 pages)
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...5 MODBUS FUNCTIONS
5.5
Loopback Test – Function Code 08
5.5.1
Loopback Test Query
The purpose of the loopback test is to test the MODBUS system, it does not affect the content
of the controller. Variations in the response may indicate faults in the MODBUS system. The
information field contains 2 bytes for the designation of the diagnostic code followed by 2 bytes
to designate the action to be taken.
Example:
A
d
d
e r
s
s
F
u
n
t c
o i
n
0
1
0
8
*These are considered to be the information fields for diagnostic mode.
5.5.2
Loopback Test Response
The response always echoes the query, only diagnostic code 0 (bytes 3 and 4) can be used.
Example:
A
d
d
e r
s
s
F
u
n
t c
o i
n
0
1
0
8
5.6
Write Multiple Coils – Function Code 15
5.6.1
Write Multiple Coils Query
Coils existing within the controller can have their state changed by this message (a maximum
of 16 coils). When used with slave address 0 (broadcast mode) all slave controllers load the
selected coil with the contents specified.
Example – a write multiple coil request to force coil 149 (auto/manual state) to ON (manual)
and force coil 150 (control action 2) to OFF (direct) in slave 01 is shown below.
A
d
d
e r
s
s
F
u
n
t c
o i
0
1
0
F
B
y
e t
C
o
u
t n
0
1
14
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D
a
a t
D
a i
g
n
o
t s
c i
D
C
o
d
e
H
g i
h
0
0
D
a
a t
D
a i
g
n
o
t s
c i
D
C
o
d
e
H
g i
h
0
0
C
o
l i
S
a t
t r
n
A
d
d
e r
s
s
H
g i
h
0
0
D
a
a t
C
o
l i
S
a t
0
1
D
a
a t
a i
g
n
o
t s
c i
D
a
a t
*
C
o
d
e
L
o
w
0
0
A
5
D
a
a t
a i
g
n
o
t s
c i
D
a
a t
C
o
d
e
L
o
w
0
0
A
5
C
o
l i
S
a t
t r
N
A
d
d
e r
s
s
L
o
w
C
9
4
u t
s
E
r r
r o
C
h
e
c
2
E
E
r r
r o
D
a
a t
*
C
h
e
c
k
F
e i
d l
3
7
D
A
E
r r
r o
D
a
a t
C
h
e
c
k
F
e i
d l
3
7
D
A
u
m
b
r e
f o
N
u
m
i o
s l
H
g i
h
C
i o
0
0
k
F
e i
d l
(
C
R
C
8
A
(
C
R
C
1 -
) 6
8
D
(
C
R
C
1 -
) 6
8
D
b
r e
f o
s l
L
o
w
0
2
1 -
) 6
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