D-85
FX Series PLC User's Manual - Data Communication Edition
Computer Link
7 Commands
7.14 TT Command [Loop-back Test]
A
Comm
on I
te
ms
B
N:
N N
etwo
rk
C
Paral
le
l Li
nk
D
Com
puter Li
nk
E
In
verter
C
omm
uni
cation
F
N
on-Proto
col
C
ommunicati
on
(R
S/RS
2 Instru
ction
)
G
No
n-
Protoc
ol
Co
mmuni
ca
tion
(FX
2N
-2
32IF)
H
Programm
ing
Comm
uni
cation
I
Re
mo
te
Ma
intenance
Apx.A
D
isco
nti
nued
models
7.14
TT Command [Loop-back Test]
The loop-back test function checks whether or not communication between the computer and a PLC is normal.
This section explains the control procedure specification method and specification example when the loop-
back test function is used.
1. Specification method
The specification method in the control procedure format 1 is shown below:
1) Specify the character length specification range while satisfying the following condition:
- 1
Character length
254
2) Express the station number, PLC number, number of device points and sum check code in hexadecimal
respectively.
2. Specification example
When executing the loop-back test to the PLC whose station number is 0 using the data "ABCDE" (while the
message waiting time is set to 0 ms)
E
N
Q
T T
S
T
X
E
T
X
Character area B
Loop-back test command
Data
(Data for
character
length)
2 characters (hexadecimal)
Character area A
2 characters (hexadecimal)
Charac
ter
lengt
h
Computer side
PLC side
Data
(Data for
character
length)
PL
C
N
o.
Sta
tio
n
No.
Mes
sage
wai
t t
im
e
S
um check
code
S
um check
code
PL
C
N
o.
Sta
tio
n
No.
Charac
ter
length
E
N
Q
This range is regarded as
the sum check target.
30
H
30
H
0 0
46
H
46
H
F F
54
H
54
H
T T
30
H
0
41
H
45
H
44
H
43
H
42
H
38
H
37
H
7 8
05
H
S
T
X
30
H
30
H
0 0
46
H
46
H
F F
02
H
E
T
X
33
H
41
H
A 3
03
H
35
H
30
H
0 5
41
H
45
H
44
H
43
H
42
H
35
H
30
H
0 5
Both data should be equivalent.
This range is regarded as the
sum check target.
Computer side
PLC side
A B C D E
A B C D E
Summary of Contents for FX-485ADP
Page 2: ......
Page 120: ...B 2 FX Series PLC User s Manual Data Communication Edition N N Network ...
Page 188: ...C 2 FX Series PLC User s Manual Data Communication Edition Parallel Link ...
Page 244: ...D 2 FX Series PLC User s Manual Data Communication Edition Computer Link ...
Page 344: ...E 2 FX Series PLC User s Manual Data Communication Edition Inverter Communication ...
Page 700: ...H 2 FX Series PLC User s Manual Data Communication Edition Programming Communication ...
Page 752: ...I 2 FX Series PLC User s Manual Data Communication Edition Remote Maintenance ...
Page 817: ......