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493
FX
3G
/FX
3U
/FX
3UC
Series Programmable Controllers
Programming Manual - Basic & Applied Instruction Edition
16 External FX Device – FNC 80 to FNC 89
16.8 FNC 87 – RS2 / Serial Communication 2
11
FNC3
0-F
NC3
9
R
otati
on and
Shif
t
12
FNC4
0-F
NC4
9
D
ata
O
per
ati
on
13
FN
C
50-FN
C
59
H
igh Speed
Pr
ocess
ing
14
FM
C
60-
FN
C
69
H
andy
In
st
ru
ct
ion
15
FNC7
0-F
N
C7
9
Ex
ter
nal
FX
I/O
D
evice
16
FN
C
80-FN
C
89
Ext
ernal FX
De
vic
e
17
FN
C
100-
FN
C
109
Da
ta
Transf
er 2
18
FN
C
110-
FN
C
139
Fl
oati
ng Poi
nt
19
FN
C
140
-F
N
C
14
9
Da
ta
O
per
ati
on 2
20
FN
C
150-
FN
C
159
Posit
ioning
C
ontr
ol
Related devices
→
For detailed explanation, refer to the Data Communication Edition.
*1.
Ch2 is not available in 14-point and 24-point type FX
3G
PLCs.
Ch0 is available only in FX
3G
PLCs.
*2.
Cleared when the PLC mode is changed from RUN to STOP.
*3.
Available in all FX
3G
PLCs and FX
3U
/FX
3UC
PLCs Ver. 2.30 or later.
*4.
Cleared when the power is turned off and on.
System configuration
For using this instruction, it is necessary to attach one of the products shown in the table below to the main
unit.
→
For the system configuration, refer to the respective PLC Hardware Edition manual.
→
For detailed explanation, refer to the Data Communication Edition manual.
*1.
Required to use ch0 (standard built-in RS-422 port) in FX
3G
PLCs.
Differences between RS (FNC 80) instruction and RS2 (FNC 87) instruction
Device
Name
Device
Name
ch0
*1
ch1
ch2
*1
ch0
*1
ch1
ch2
*1
M8371 M8401 M8421 Sending wait flag
*2
M8370 D8400 D8420 Communication format setting
M8372 M8402 M8422 Sending request
*2
–
−
−
M8373 M8403 M8423 Receiving complete flag
*2
M8372 D8402 D8422
Remaining number of data to be
sent
*2
–
M8404 M8424 Carrier detection flag
M8373 D8403 D8423 Monitor for number of received data
*2
–
M8405 M8425 Data Set Ready (DSR) Flag
*3
M8375 D8405 D8425 Communication parameter display
–
–
–
–
M8379 D8409 D8429 Time-out time setting
M8379 M8409 M8429 Time-out check flag
M8380 D8410 D8430 Header 1, 2
–
−
−
−
M8381 D8411 D8431 Header 3, 4
M8382 D8412 D8432 Terminator 1, 2
M8383 D8413 D8433 Terminator 3, 4
M8384 D8414 D8434 Receiving sum (received data)
M8385 D8415 D8435 Receiving sum (calculation result)
M8386 D8416 D8436 Sending sum
M8389 D8419 D8439 Operation mode display
M8062 M8063 M8438 Serial communication error
*4
M8062 D8063 D8438
Error code number of serial
communication error
*4
PLC
Communication type
Option
FX
3U
,
FX
3UC
-32MT-LT(-2)
RS-232C communication FX
3U
-232-BD or FX
3U
-232ADP(-MB)
RS-485 communication
FX
3U
-485-BD or FX
3U
-485ADP(-MB)
FX
3UC
(D,DSS)
RS-232C communication FX
3U
-232ADP(-MB)
RS-485 communication
FX
3U
-485ADP(-MB)
FX
3G
RS-232C communication
FX
3G
-232BD or FX
3U
-232ADP(-MB) (which requires FX
3G
-CNV-ADP)
RS-232C/RS-422 converter
*1
(FX-232AW, FX232AWC and FX-232AWC-H)
RS-485 communication
FX
3G
-485-BD or FX
3U
-485ADP(-MB) (which requires FX
3G
-CNV-ADP)
Item
RS2 instruction
RS instruction
Remarks
Header size
1 to 4 characters (bytes) Up to 1 character (byte)
For the RS2 instruction, up to 4 characters (bytes)
can be specified as a header or terminator.
Terminator size 1 to 4 characters (bytes) Up to 1 character (byte)
Attachment of
check sum
The check sum can be
automatically attached.
The check sum should
be attached by a user
program.
For the RS2 instruction, the check sum can be
automatically attached to the sent and received data.
In this case, however, make sure to use a terminator
in the communication frame to be sent and received.