Mitsubishi Electric FX3U-232-BD User Manual page 619

FX Series PLC User's Manual - Data Communication Edition
Non-Protocol Communication (RS/RS2 Instruction)
2. Time at which receiving is completed
Receiving is completed in the following three conditions. When either condition is established, receiving is
completed.
1) When the PLC receives the amount of receive data specified by the RS2 instruction
2) When the "terminators", "sum check" and "CR + LF" set in the communication format are received normally.
.......... Data
.......... Data
.......... Data
.......... Data
.......... Data
3) When data receiving is suspended and the PLC does not receive the next set of data within the time set
within the time-out time setting device (D8379, D8409 or D8429), the time-out check flag (M8379, M8409
or M8429) turns ON.
3. Operation of time-out check flag
When data receiving is suspended, if the PLC does not receive the next set of data within the preset time-out
time setting, the time-out check flag is set to ON.
At this time, the receiving complete flag is also set to ON.
The time-out judgment time can be set in the following range:
Setting range for ch0 and ch2: 1 to 3,276 (10 to 32,760 ms)
Setting range for ch1: 1 to 255 (10 to 2,550 ms)
Name
Time-out check flag
Time-out time setting
Receiving
Data
Time-out check flag
M8409
Receiving complete
M8403
The time-out check flag does not turn OFF automatically. Set it to OFF in the sequence program. (When the
receiving complete flag is set to OFF, the time-out check flag is also set to OFF.)
By using this function, the PLC can receive data from equipment where the amount of send data varies
without the terminator.
4. When the control line is set to the interlink mode
When the interlink mode is selected in the communication format, the following sequence is adopted from
start of receiving to completion of receiving:
1) When the amount of data already received becomes "preset amount of received data -30", the control line
ER (DTR) turns OFF.
When the control line ER (DTR) turns OFF, the external equipment should suspend data sending.
After the control line ER (DTR) turns OFF, the PLC can receive up to 30 characters (bytes).
2) When the external equipment suspends data sending, the PLC sets the time-out check flag and receiving
complete flag to ON after the preset time-out time setting.
Move the received data in a sequence program, and then set the receiving complete flag and time-out
check flag to OFF.
3) When the receiving complete flag is set to OFF, the control line ER (DTR) turns ON.
When the control line ER (DTR) turns ON, restart data sending from the external equipment.
4) Repeat steps 1) to 3) until data receiving is completed.
CR+LF
Terminator
Terminator CR+LF
Terminator Sum check
Terminator Sum check
ch0 ch1 ch2
M8379 M8409 M8429
D8379 D8409 D8429
Receive data is suspended.
Set to OFF in sequence program.
D8409
 10 ms
ON
ON
8 Creating Programs (RS2 Instruction)
CR+LF
8.2 How to Use RS2 Instruction
Apx.A
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