Mitsubishi FX2 "Transistor Unit"

Have a customer that normally keeps a machine powered down, only turning it on every 2 or 3 weeks to run as needed. Last time it ran OK, today it showed Battery & CPU error LED's.
Replaced the battery & bought a copy of the program from the original manufacturer, downloaded it & went into monitoring mode.
The PLC showed RUN LED on, the inputs respond but NONE of the outputs turn on (on the bench) even though monitoring shows they are. I even wrote my own little program to monitor each input & turn on all outputs if input X0 is on. According to monitoring all inputs are reading & when X0 is on it shows all 16 outputs on - but their not - no LED's & no continuity across the outputs.

My question is: this is labelled a TRANSISTOR UNIT - do the outputs maybe have to be fully wired before they will turn on? To me it seems the LED's should come on regardless. It's just strange that all the outputs would die because of a dead battery. Or is there something else that needs to be done/set for this?

The FX2 can be configured for an input to put it into 'run' mode.

The run light is lit and when monitoring the outputs appear to be on (but are not)

Check parameters (plc system 1) to see if an input is configured for this.
Any input between X0 to X17 can be used and it must be on to run.

Ronnie,

Thanks - never encountered this before, still learning after 30 years,

(Wonder if I'll ever learn it all???)

If this was the case with your plc then you were double unlucky.

I have only ever seen X0 used as the 'run' input (usually connected to some safety device)

'Learn it all' never!

Aabeck said:

I even wrote my own little program to monitor each input & turn on all outputs if input X0 is on. According to monitoring all inputs are reading & when X0 is on it shows all 16 outputs on ...

Click to expand...

This clearly mentions the PLC running and the LEDs not lit for the outputs monitored On.
If the scenario is true, it has nothing with stop by an input signal.
I would suspect the unit is defective.

Sergei Troizky said:

This clearly mentions the PLC running and the LEDs not lit for the outputs monitored On.
If the scenario is true, it has nothing with stop by an input signal.
I would suspect the unit is defective.

Click to expand...

I concur with Sergi. If a run input needs to be on for the unit to be in run mode, and that input is not on, there would be no green run LED on the unit like the OP stated.

Dave

Have you tried it with an FX 2n?

Took it back to the customer's shop & installed it, remember on the bench it showed RUN mode & monitoring showed the outputs were being controlled - but none were turning on.

When I powered up machine with the PLC fully wired, the outputs came on!

I tried to find the PLC System 1 parameter. but am not that familiar with GX Developer so I didn't find which input was preventing the run mode (I know it's not X0 'cause that's the one I tried on the bench). But it's running fine & the customer is happy.

EDIT: It just wanted to be a headache.

Good. I know that feeling - 'hoping it works but not sure'.
Case proven M'lord I think

If I remember correctly, the FX2 has a separate RUN input terminal to the left of X0 which has to be on.
That input has to be ON and maintained for RUN mode.

Other models had 2 momentary software configurable Run/Stop inputs, using dedicated inputs: (X0,X1).

That was just the FX model. Long before the FX nn models

Whatever it was I'm just glad it works.

Thanks Ronnie.