Mitsubishi FX3U-232-BD User Manual page 511

FX Series PLC User's Manual - Data Communication Edition
Non-Protocol Communication (RS/RS2 Instruction)
11.4 Checking Sequence Program
1. Communication settings in a sequence program
Verify that N:N Network (D8176 to D8180) and parallel link (M8070 and M8071) are not set.
Verify that the communication format (D8120, D8400 or D8420) is set correctly. If a communication port is set
more than once, communication is not possible.
After changing any settings, make sure to turn OFF the PLC power, and then turn it ON again.
2. Communication settings using parameters
Verify that the communication settings using parameters are correct. If the contents of the settings do not
agree, communication will not function correctly.
After changing any settings, make sure to turn OFF the PLC power, and then turn it ON again.
3. Presence of VRRD and VRSC instructions (except FX
Verify that the VRRD and VRSC instructions are not used in the program.
If these instructions are used, delete them, turn OFF the PLC power, and then turn it ON again.
4. Presence of IVCK, IVDR, IVRD, IVWR, and IVBWR instructions (in FX
Verify that the IVCK, IVDR, IVRD, IVWR and IVBWR instructions are not being used for the same channel.
If these instructions are used for the same channel, revice them, turn OFF the PLC power, and then turn it ON
again.
5. Presence of EXTR instruction (in FX
Verify that the EXTR instruction is not used in the program.
If this instruction is used, delete it, turn OFF the PLC power, and then turn it ON again.
6. Presence of RS and RS2 instruction
Verify that two or more RS/RS2 instructions are not being driven for the same channel.
If two or more RS/RS2 instructions are driven, modify the program so that only one RS/RS2 instruction is
driven.
11.4.1 Checking communication port settings (in FX
1. Checking the operation mode
In FX and FX
3U 3UC
D8419 stores the communication type code currently adopted in communication port ch1.
D8439 stores the communication type code currently adopted in communication port ch2.
The table below shows the contents of the communication type codes.
Code
0
2
3
4
5
6
7
If the operation mode is different, check the parameters and sequence programs.
2N
PLCs, the communication port operation status can be checked.
Programming communication
Protocol dedicated to computer link
N:N Network
RS instruction
RS2 instruction
Parallel link
Inverter instruction
and FX
3U
and FX PLCs)
2NC
and FX
3U 3UC
Description
11 Troubleshooting
11.4 Checking Sequence Program
PLCs)
3UC
and FX PLCs)
3U 3UC
PLCs)
A
B
C
D
E
F
G
H
I
Apx.
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