I have a FX3U48M Delema

Greg7683

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Jun 2018
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Plainfield IN
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OK I have FX3U48 MR/ES-A And it seems to stop giving the signal Threw Y7 to start the belt to take the product to another conveyor. The Y7 on the bottom of the PLC connects to the bottom of the 24V relay coil and the top of the coil is connected to the 24V+ of the FX2N 16 EX controller.



The only way I can get the belts to move is if I jumped a wire from the -24V of the converter to the bottom of the relay which makes the belts run all the time. I tried a new PLC New relay replaced the photo sensors tried to reenter the program in to the PLC from another since they are all programmed and wired up the same and nothing seems to work I even ran new cables from the main box to the belts and nothing seems to fix this problem.




Any suggestions?
 
Just to make clear. Fx2N-16EX is not controller, it is digital input card and it's S/S signal should be connected to +24V or -24V depending what do you want - sink or source input. By your information it's connected to +24V so it is sinked, meaning that by applying 0VDC to FX2N input will give to PLC program signal that the mentioned relay contact is opened or closed depending how it is wired. Did you checked relay wiring?
Does it's LED changes the state when you apply voltage to relay's coil?
On other side FX3U-48MR/ES ist PLC and it has rela outputs, so it should be very easy to check does it has faulty output. Is it Y7 output (as you wrote) LED on? When the LED is on you can try is the output also working...
But in reality it is hard to troubleshoot without application and PLC connected to PC.
 
I would say check that the inputs light up the appropriate LED's on the PLC. Then get into the program in 'monitor mode' (so that you can 'see' that the inputs are making it into the PLC program). Verify that the inputs come and go as they ought. Then locate the rung with the output Y7 and see which relay contacts are not closing to activate it. You should also be able to 'force' contacts in the program to turn them on and verify if the PLC can really actuate the output and drive the motor.
Poet.
 
Y7 is lit up on the PLC but nothing happens. Will check with the program the bad thing is there are no comments anywhere only like Y007 and X001 so I have to spend time tracking down sensors and other stuff lol.

20180818_054943.jpg
 
Hmmmm.
Y7 output is lit but nothing happens.
Is there 24 volts across the relay coil?

The Y7 output . . is it supposed to be providing + 24 Vdc?
Or is it supposed to provide a ground to the coil?
Is Y7 a relay output? If so is the other side of the contact wired to provide what the relay requires?

Poet.
 
From what I was told it is supposed to be 0v at y7 the only way for me to get the contactor/relay to pull in is to add a wire from the negative on the 24V converter to the bottom of the contactor relay
 
Greg,
I will write you some advices regarding your problem, but the first one would be to hire someone with more experience in PLC and wiring, because you can make more financial harm if you don't do.
If you don't want to employ someone else then you can try following:
If I remember good "COM2" is common for Y4, Y5, Y6, Y7, so first thing I would do would be to check is COM2 connected to 0VDC. If yes, I would check if COM2 and Y7 is closing when Y7 LED is ON. Is yes then I would check if COM2 is grounded. All this presuming that outputs are sinked...
 
If I could hire someone that knows about this stuff I would but it's not up to me. So I am stuck trying to figure this stuff out. So that's why I am here to find some help with learning a bit more on how this stuff works and to learn how to trouble shoot it.


Like in the program when i monitor it most of the sensors have like timers in the program like one has T22 and when you put your hand over the sensors the 0 starts counting for a short period of time before it stops When I monitor Y007 that's on the wire that is connected to the bottom of the contractor I can see the sensors light up blue but the 0 on the timer I am guessing that's what the T22 is doesn't start counting like the rest do.
 

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