Plc power indicator on but run and error indicators off

[Syahmi Noordin]

Hello..I am new to Plc.I have Mitsubishi Melsec Fx3Ga-40MR PLC controlling a machine for packing powder.Currently the Plc has issue which power indicator on but run and error indicators off.I tried to connect it using usb(Easy driver) with my laptop(GX works 2 software) but got no communication.I tried to access device manager in my laptop,Usb socket driver under usb port not showing.
The weird thing is I can connect with other machine which exactly the same as Im troubleshooting now using same cable and software.
I suspect the Plc has lost its program so I need to download the program to it.
For your information,The inputs and outputs of the Plc all indicators not turn on.
I checked got 24Vdc from external power supply.
Sensors connection to input port of Plc all are functioning.
May I get your fellows expert and experienced help about this issue?
Thank you.

 

[parky]

Never heard of Easy driver so cannot comment on if that could be the problem getting on-line, normally you use the SC09 or equivelent 232 to 422 cable or the USB to 422. I would check that somebody has not switched the run switch off, There is on some models of FX where if set in the setup one of the inputs is used as a RUN command so needs to be on.
Seems weird you have no inputs so only things I can think of is loss of common to the PLC inputs or loss of power to those, there will be no outputs on unless the PLC is in run mode.

 

[Syahmi Noordin]

Hi parky.Thanks for your feedback.I tried to check the wiring okay and the switch already in run mode.I already replaced with new same Plc now can communicate and running.Due to the communication issue before,Im suspecting there is problem on motherboard whether port or internal components.

 

[parky]

It sounds like that's the problem, very rare for a Misi to go faulty, I have been involved with Mitsi since 1984 & only ever had one completly down & that was due to an over eager hygine guy with a high pressure hose, the only other time was an input was permanly on even when disconnected.