mitsubitshi fx2nc output problem

i have a problem with the output of our plc...

the plc shows the appropriate outputs on the LED displays (according to our ladder program) but there is no output for some of the outputs after the ribbon cable connection of the plc

it worked initially and then there was no output and not ever since

but the rest work fine!
what is the problem? can someone pls help?

You will probably discover that those "some outputs" share the same common. Check for voltage at that common terminal. If it's there, then see if there's a blown fuse in the output module. If it's not there, find out why.

It would help if you tell us what brand/model PLC.

beerchug

-Eric

Ah, yes Pierre...

Note to self: Always look at the subject line...

beerchug

-Eric

monitor the ofram

Keeying
Can you connect with your plc and monitor your program execution to ensure that this output is already on .may be the leds are on due to a hardware error this could occur also you may have a burnt outputs if your outputs is transistor output in this case the outputs leds on and you have nothing work.Is you ribbon cable is ok.
best luck

It worked initially!!!

It worked what? What is the output hooked up to?

Check your's power supply at common

Let check your power supply at the common, also if you use relay
output modules ..please check small relay inside ..is it dead or not
(check relay contact and coil in side plc)

Just from my little brain...
platootod

thanx 4 yer replies folks!

anyway, i think i might have killed the outputs or something like blown da fuse? but i was wonderin' if each output have individual fuses coz others still work fine...

and i don't think they're on due to hardware failure coz it responds to da inputs according to our ladder diagram

and about what hardware it's connected to, we tried different stuff to test it like a voltmeter, a buzzer, solenoids...

and about the ribbon cable, we tried it with another ribbon cable and got the same thing...

we decided to change our program by reducing outputs... by changing the hardware used.
i would sure like to find out what went wrong
just in case it happens again to the other outputs!

Common supply

What the others are saying is that on PLC's, certain groups of outputs share their supply. This is normally about 8 outputs on most modern PLC's, in the past it may have been only 1 or 2. If you have blown part of the circuit of one output it might have taken out it's supply which also supplies some other outputs. Check for fuses on the output side as you've probably blown one.