D-79
FX Series PLC User's Manual - Data Communication Edition
Computer Link
7 Commands
7.13 On-demand Function
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
2. When ch2 is used in FX
3G
, FX
3GC
, FX
3U
and FX
3UC
PLCs
Point
• The on-demand send processing signal (M8127 or M8427) turns ON when the PLC gives a request to
send data to the computer, and turns OFF when sending of the specified data is completed. Use this signal
for interlock to prevent giving two or more on-demand requests at the same time.
• While the on-demand send processing signal is ON, the PLC cannot receive commands sent from the
computer.
• Amount of on-demand data and number of data registers used for sending according to the unit
specification (word or byte)
When the specified unit is a word:
The amount of on-demand data is equivalent to the number of data registers to be sent.
When the specified unit is a byte:
Two on-demand data units use one data register for sending.
Example: When the amount of on-demand data is "5", the number of data registers for sending is "3".
Device
Name
Description
M8427
On-demand send
processing
Remains ON while the on-demand function is being executed.
ON: On-demand data is being sent.
OFF: Sending of on-demand data is completed.
M8428
On-demand error flag
Turns ON when an error is included in a specified value to be sent in the on-
demand function.
ON: Error is included.
OFF: Error is not included.
M8429
On-demand byte/word
changeover
Specifies the unit (byte or word) of data handled in the on-demand function.
ON: Unit = Byte (8-bit)
OFF: Unit = Word (16-bit)
D8427
On-demand head device
number specification
Sets the head data register device number containing the data to be sent
using the on-demand function in a sequence program.
D8428
On-demand data quantity
specification
Sets the amount of data to be sent using the on-demand function in a
sequence program.
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 ...
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