F-47
FX Series PLC User's Manual - Data Communication Edition
Non-Protocol Communication (RS/RS2 Instruction)
8 Creating Programs (RS2 Instruction)
8.1 Checking Contents of Related Devices
A
Common Items
B
N:N Network
C
Parallel Link
D
Computer Link
E
Inverter
Communication
F
Non-Protocol
Communication
(RS/RS2 Instruction)
G
Non-Protocol
Communication
(FX
2N
-232IF)
H
Programming
Communication
I
Remote
Maintenance
Apx.
Discontinued
models
8. Creating Programs (RS2 Instruction)
This chapter explains how to create programs for non-protocol communication using RS2 instruction and how
such programs operate.
RS2 instruction is supported only in FX
3U and FX3UC PLCs.
RS2 instruction has the following additional functions which are not provided in the RS instruction:
1) Up to 4 characters (bytes) can be specified as the header and terminator.
2) The sum check can be added automatically.
3) The communication port (channel) can be specified.
8.1 Checking Contents of Related Devices
The tables below show devices used in non-protocol communication using RS2 instruction.
1. Bit devices
R: Read only
R/W: Read or Write
*1. Available in Ver.2.30 or later of FX3U or FX3UC PLC
Device
Name Description R/W
ch1 ch2
M8063 M8438
Serial communication
error
This device turns ON when a communication error occurs.
When this device (serial communication error) turns ON,
D8063 or D8438 stores the corresponding error code.
R
M8401 M8421 Sending wait flag This device remains ON while the PLC is waiting to send. R
M8402 M8422 Sending request When this device is set to ON, the PLC starts to send. R/W
M8403 M8423 Receiving complete flag
This device turns ON when receiving is completed.
While this device (receiving complete flag) is ON, the PLC
cannot receive any receive data.
R/W
M8404 M8424 Carrier detection flag
This device turns ON in synchronization with the CD (DCD)
signal.
R
*1 M8405 M8425 Data set ready (DSR) flag
This device turns ON in synchronization with the DR (DSR)
signal.
R
M8409 M8429 Time-out check flag
This device turns ON when data receiving is suspended and
the next set of receive data is not given within the time set by
the time-out time setting device.
R/W
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