(6) Check that the total 5V DC internal current consumption and total 24V DC current are within the capacity of the power distribution
9.1 When I/O data cannot be communicated
When I/O data cannot be communicated between the master station and MELSEC-ST system, troubleshoot the problem according to the following flowchart.
I/O data cannot be communicated
Refer to Section 9.1.1.
Yes
No
Yes
No No
Yes
No
Yes
Refer to Section 9.1.2.
1) (To next page)
Refer to Chapter 9.
Yes Yes
No No Is the MELSEC-ST system
configured correctly?
Are the SYS. LEDs and AUX. LEDs of all power distribution modules on?
Is the RUN LED of the head module on?
Are slice modules mounted on all base modules?
Is the RUN LED of each slice module on or flickering?
Is the BF LED of the head module off?
Mount slice modules on all base modules.
Take corrective action for the case where the RUN LED is off.
Refer to the manual of the corresponding slice module.
Switch on the external power supplies of all power distribution modules.
9
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9 TROUBLESHOOTING
MELSEC-ST
Yes
No Refer to Section 9.1.3.
Complete
No Refer to Section 9.1.4.
Yes 1)
Refer to Section 9.2.
No
Yes
Is the ERR. LED of the head module off?
Are correct input data sent to the master station?
Are correct output data sent from the master station?
9 TROUBLESHOOTING
MELSEC-ST
9.1.1 When RUN LED is off
When the RUN LED of the head module is off, troubleshoot the problem according to the following flowchart.
RUN LED is off
Yes
No
No
Yes
Yes
No Yes
Are the FDL address No setting switches set to the FDL address (0 to 99) of the
slave station?
Is the bus refreshing module for power supply mounted next to the right of the
head module?
Is a power suppliable type base module used for the bus refreshing module that
powers the head module?
Does the bus refreshing module have a sufficient power supply capacity?
Please consult your local Mitsubishi representative, explaining a detailed description of the problem.
Set the FDL address setting switches to the FDL address (0 to 99) of the slave station.
Mount the bus refreshing module next to the right of the head module.
Replace the base module for the bus refreshing module with a power suppliable type base module.
Calculate the total current consumption of the slice modules powered by the bus refreshing module, and add another bus refreshing module.
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MELSEC-ST
9.1.2 When BF LED is on
When the BF LED of the head module is on, troubleshoot the problem according to the following flowchart.
Are the slave parameter and FDL address setting switches set to the same
FDL address?
Does the Select Modules setting match the actual system configuration? 1
Is the master station operating normally?
(Has PROFIBUS-DP communication started?)
Is the communication connector connected?
Check the wiring conditions.
Is the number of repeaters within 3?
Is each segment length within the specification range?
Are bus terminators connected at both end of each segment?
Is the number of devices connected in each segment within the specification range?
Is the PROFIBUS cable wired without wire breakage?
If the problem still persists after checking the wiring conditions, please consult your local Mitsubishi representative, explaining a detailed description of the problem.
Set the slave parameter and FDL address setting switches to the same FDL address.
(Refer to Section 5.3 and Section 6.2.)
Change the Select Modules setting to match the actual system configuration.
(Refer to Chapter 6.)
Refer to the master station manual and counter the problem.
When the slave parameter setting is wrong, the error code of the head module is stored into the extended diagnostic information area of the master station.
Refer to Section 9.2.2 for details of the error code.
9 TROUBLESHOOTING
MELSEC-ST
9.1.3 When input data is erroneous
When the input data sent from the head module is erroneous, troubleshoot the problem according to the following flowchart.
No
No No
Cancel (UNFREEZE) the FREEZE service of the global control function.
(Refer to Section 4.2.2.)
Confirm the maximum input/output points of the head module, and check data at the correct offset address.
(Refer to Section 3.2.1.)
The head module or slice module may be faulty. Please consult your local Mitsubishi representative, explaining a detailed description of the problem.
Input data is erroneous
Is the FRE. LED of the head module off?
Is the offset address of the checked input data correct?
Yes
Yes Yes Yes
Refer to the manual of the corresponding slice module.
No Refer to the manual of the corresponding slice module.
Is the external wiring of each slice module correct?
Are the RUN and ERR. LEDs of each slice module OFF?
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MELSEC-ST
9.1.4 When output data is erroneous
When the output data received by the head module is erroneous, troubleshoot the problem according to the following flowchart.
Yes
No
No
Yes
No
Yes Yes
Cancel (UNSYNC) the SYNC service of the global control function.
(Refer to Section 4.2.2.)
Confirm the maximum input/output points of the head module, and check data at the correct offset address.
(Refer to Section 3.2.2.)
The head module or slice module may be faulty. Please consult your local Mitsubishi representative, explaining a detailed description of the problem.
Is the SYN. LED of the head module off?
Is the offset address of the checked output data correct?
Refer to the manual of the corresponding slice module.
Output data is erroneous
No Refer to the manual of the corresponding slice module.
Is the external wiring of each slice module correct?
Are the RUN and ERR. LEDs of each slice module OFF?