105 run mode

[plcnut]

I have a 105 plc that sat for about a year and when I powered it up to use it, I could not get it to go into run mode. It had worked fine when I had last powered it down. when I hooked up my computer it said that it was in program mode, when I set it back to run mode everything was fine. Why wouldn't it go into run mode when I cycled the power? and what can I do to prevent this problem in the future?

[franji1]

I don't think 105s are battery backed.  They have a super capacitor, which definitely ran out after a year 

So the chance of ladder logic becoming scrambled, and hence not going into RUN mode is probably right.

You should be able to download the program again and go to RUN???

[plcnut]

Yes, I was able to put it back into run mode and everything was great. This thing only gets used once a year, Is there anything I can do to set it back into run mode without having to hook up to it with a computer? I don't know if I am always going to be there when they need it to run.

[franji1]

I have no idea.  The 105 is not a Host Engineering product, it's made by Facts Engineering.

You'll get a better response on the automationdirect forum http://forum1.automationdirect.com

[plcnut]

Thanks, I'll try that.

[Controls Guy]

Maybe disassemble the unit, and run the leads out to a large external capacitor in lieu of the bitty internal one?  Make sure to put a resistor in series to limit charge rate.