Mitsubishi FX3U-232-BD User Manual page 485

FX Series PLC User's Manual - Data Communication Edition
Non-Protocol Communication (RS/RS2 Instruction)
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
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
Device
ch1 ch2
M8063 M8438
M8401 M8421
M8402 M8422
M8403 M8423
M8404 M8424
*1 M8405 M8425
M8409 M8429
R: Read only
R/W: Read or Write
*1. Available in Ver.2.30 or later of FX3U or FX3UC PLC
and FX
3U
Name
This device turns ON when a communication error occurs.
Serial communication
When this device (serial communication error) turns ON,
error
D8063 or D8438 stores the corresponding error code.
Sending wait flag This device remains ON while the PLC is waiting to send.
Sending request When this device is set to ON, the PLC starts to send.
This device turns ON when receiving is completed.
Receiving complete flag While this device (receiving complete flag) is ON, the PLC
cannot receive any receive data.
This device turns ON in synchronization with the CD (DCD)
Carrier detection flag
signal.
This device turns ON in synchronization with the DR (DSR)
Data set ready (DSR) flag
signal.
This device turns ON when data receiving is suspended and
Time-out check flag the next set of receive data is not given within the time set by
the time-out time setting device.
8 Creating Programs (RS2 Instruction)
PLCs.
3UC
Description
8.1 Checking Contents of Related Devices
R/W
R/W
R/W
R/W
F-47
A
B
C
D
R
E
R
F
R
R
G
H
I
Apx.