Checking Sequence Program - Mitsubishi FX3U-USB-BD User Manual

FX Series PLC User's Manual - Data Communication Edition
Inverter Communication
11.4

Checking Sequence Program

1. Communication setting in the sequence program
Verify that N:N Network (D8173 to D8180) and parallel link (M8070 and M8071) are not set.
After changing any setting, make sure to turn OFF the PLC power, and then turn the power ON again.
2. Communication setting using parameters
Verify that the communication settings using parameters are correct. If the contents of the parameters do not
agree, communication will not function correctly.
After changing any parameters, make sure to turn OFF the PLC power, and then turn the power ON again.
3. Presence of VRRD and VRSC instructions
1) Except FX
3U
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 PLC
3G
- 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 RS instruction (in FX
Verify that the RS 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.
5. Presence of RS and RS2 instructions (in FX
Verify that the RS and RS2 instructions are not being used for the same channel.
If these instructions are used for the same channel, delete them, turn OFF the PLC power, and then turn the
power ON again.
11.4.1 Checking inverter operation status
1. When the operation mode of an inverter is not changed over to computer link mode
1) Verify that the inverter is set to the external operation mode.
2) Verify that no signal is being input to the external terminals STF and STR.
3) Verify that the correct operation mode changeover program is being executed.
2. When an inverter cannot be started even in computer link mode
1) Verify that the program for starting the inverter is executed correctly.
2) Verify that the operation command and speed command are set correctly.
3) Verify that the allowable communication time interval is set correctly.
3. When an inverter is stopped by an alarm during operation due to defective communication
1) Verify that a communication cable is connected correctly between the PLC and the inverter.
(Check for poor contact or wire breakage.)
2) Verify that a sequence program is created so that communication is executed with each inverter within a
constant cycle. Set the communication check time interval to a large value, and check the communication
status.
3) Verify that the allowable communication time interval is set correctly.
4) Verify that terminal resistors are wired correctly.
E-112
and FX PLCs
3UC
2N
and FX PLCs)
2NC
, FX and FX
3G 3U
11 Troubleshooting
11.4 Checking Sequence Program
PLCs)
3UC