Hi all Logo users.

Yesterday I got my Startkit 12/24RCE + KTP400 and was doing a setup. I feel like Ferdinane and was not alert what I was doing. So I connect the Logo 12/24v to 230v... in less 1s power.

I though to myself the Logo was died.

The fuse 10A melt and the power was off.

Change the fuse and this time I didn't forget the Power module. The surprise was the Logo was not died but it come little smoke and it smell little. The smell was gone after a few minutes and the smoke was less half second.

So the question  are:

Was a lucky that Logo didn't died or does Logo have some protection I have missed ??

Regads 

ixo65

You were very lucky.

 I hope so....

I will do more test in the weekend... so fare I have not seen anything wrong with it.

I read somewhere that ground is not needed for LOGO because it has double shield

and maybe that save me or maybe it has nothing to do with my bad approach.

ixo65

I'm guessing that there is a voltage dependent resistor (VDR) in the LOGO that controls the LOGO for an overvoltage in the power supply. And this VDR will be destroyed.
Hence the smoke.

 You are right, I just open the LOGO and on the backside of the components on the PCB was a black dust that was able to clean... and destroyed components.

I live in Sweden so who will I contact to do any service on Siemens products ??

Hello FredrikS7,

A voltage-dependent resistor (VDR) in a Logo 24VDC is not to be expected. Rather, the voltage regulators will have exploded. The 230V are probably completely broken through and the processor is therefore also dead.

All in all, this is definitely a total loss. Any attempt at repair is absolutely uneconomical. All you have to do is buy a new one and install the back-up program.

Ella_68

Ella_68

A voltage-dependent resistor (VDR) in a Logo 24VDC is not to be expected. Rather, the voltage regulators will have exploded. The 230V are probably completely broken through and the processor is therefore also dead.

 Thanks for your respond.

Today and late yesterday I did a simple program to change the screen in sequence programmer

I have run every function from LogoSoft to LOGO plc and it works. I have start the web server and access it from IP. I have test some programs like the one below.

Sequence programming: The LOGO display white background, amber to red and start over.

So from my stand I couldn't find yet anything wrong with it.

Maybe in today age Swedish power is more clean... ;)

The only PCB board of 3 I could see something wrong was on the backside on Power and Relay board.

And lastly I got 24,3V on all 4 outputs

So time is also important factor when high voltage would brake a circuit or not, same its for a human. My guessing is the VDR made my fuse to melt very quickly and saved my LOGO. 

Ps. I will contact Siemens Stockholm office next week...

I can only say that you were very lucky! Normally this ends deadly for the logo.

Ella_68