Mitsubishi FX3U-232-BD User Manual page 499

FX Series PLC User's Manual - Data Communication Edition
Non-Protocol Communication (RS/RS2 Instruction)
8.4 Important Points in Creating Programs
1) RS2 instruction can be used as many times as necessary in a program, but make sure that only one RS2
instruction is driven in each communication port at a time.
For multiple RS instructions to be driven, make sure the OFF time is longer than one scan time.
2) Do not use another instruction (such as RS instruction or IVDR instruction) which uses the same
communication port. If such an instruction is used, communication may not function normally.
3) While RS2 instruction is being driven, change of D8400 or D8420 is prohibited.
To change D8400 or D8420, set the RS2 instruction to OFF, set D8400 or D8420 to "0", and then set a
new value to D8400 or D8420.
4) In the interlink mode, set the amount of received data "n" to "31" or more.
If it is set to "30" or less, the control line ER (DTR) is set to OFF as soon as the PLC receives data.
5) FX and FX
3U
bidirectional communication, pay attention not to turn ON the sending request flag while receiving.
6) When using the header and terminator, set them before driving the RS2 instruction. Do not change the
setting while the RS2 instruction is being driven.
8.5 Communication Error
When a communication error occurs, the error flag M8063 turns ON during communication using ch1, or the
error flag M8438 turns ON during communication using ch2.
D8063 or D8438 stores the error code respectively.
Error code
D8063 (ch1) D8438 (ch2)
6301
6303
6304
PLCs execute full-duplex, bidirectional communication. When using half-duplex,
3UC
3801 Parity error, overrun error or framing error
3803 Receive data sum mismatch
3804 Defective data format
8 Creating Programs (RS2 Instruction)
Description
→ Confirm the contents in "Chapter 11. Troubleshooting".
8.4 Important Points in Creating Programs
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