F-82
FX Series PLC User's Manual - Data Communication Edition
Non-Protocol Communication (RS/RS2 Instruction)
11 Troubleshooting
11.4 Checking Sequence Program
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, D8370, 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 the power 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 the power ON again.
3. Presence of VRRD and VRSC instructions
1) Except FX3U and FX3UC PLCs
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 the power ON again.
2) FX
3G PLC
- In the case of the 14 points and 24-point type
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 the power ON again.
- In the case of the 40 points and 60-point type
Verify that the VRRD and VRSC instructions are not used in the program.
If these instructions are used in the program, the communication function is not available in ch2.
Use ch1, or delete these instructions.
After deleting these instructions, turn OFF the PLC power, and then turn the power ON again.
4. Presence of IVCK, IVDR, IVRD, IVWR, and IVBWR
*1
instructions (in FX3G, FX3U and FX3UC
PLCs)
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, revise them, turn OFF the PLC power, and then turn the
power ON again.
*1. The IVBWR instruction is supported only in FX
3U and FX3UC PLCs.
5. Presence of EXTR instruction (in FX2N and FX2NC PLCs)
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 the power 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.
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