Load Moment Indicator

[Impact]

Ok, gimme ideas.

Yesterday I got a call from the operator using the 50 ton AT Grove. He had all the main out, the job, and slider pulled, 170' tip hieght basucally. He'd picked a small part with a weight of about 1,200 pounds. the LMI showed he had 3,500 pounds, although it was still within it's rating. He had a boom angle of 74 degrees. He got off the rig to assist the riggers. Whenever he got back in the cab, the angle sensor showed him at 79 degrees, and 6,500 pounds, both out of it's rated weight and range. The Grove has a maximum of 78 degrees. He boomed down to about 65 degrees and got the alarms to go off (after setting the 1200 pound load down of course). He called me about what to do.

I recommended he draw the boom all the way in and lay it down horizontal, then kill the engine for a few minutes. He did, waited a bit, and tried again. Same thing. It had gone crazy. We tried calling a couple of people, but most were closed for the day. One guy said it had to be the degree indicator or a circuit board. I was thinking it could be any number of things.

Anywho...We went back to the job this morning, cranked it up, and it's now running fine.

So...do you dig into it or wait till it goes brain dead again? Will it go brain dead during a critcal lift?

 

[Tiny]

May not be your problem but on 2 Demags and a 5150 Grove we have had so much rain that the box's on the reels and one other stuck out on the boom had water in them.pull the covers and dry them out and back to work.

 

[heavylift]

I had one go crazy in the early nineties on a new 28 ton grove... It would shut all the functions down that would make a lift unsafe.... but the crane didn't have a load on it..

restart reset was much help
Grove techs crawled all over it for 2 days... replaced lots of stuff... sorry can't tell what they replaced

 

[liebherr1160]

a few things pop into mind
Was it windy enough to whip the boom length/A2B cable around?
Was there a ready mix or dry wall truck around?

I found that the Pat system especially would get cranky in a sudden temperature swing..Condensation..I hated the DS50 system for this..the DS350 also had its moments.The angle pot,lenght pot,plus the electrical swivel in the Pat Black boom mounted box may need a little shot of electrical parts cleaner ..a little oxidation would be enough to cause it to stick.just go stupid

On the 900E I actually had the angle weight get stuck on a screw :beatsme..had to slack it off and move it a little bit further out on the spline..

Im guessing the Grove At has a Pat Ds system ..a 350 maybe?
Occasionally the ram gets cluttered..after its shut down I believe it takes the board mounted re-chargeable battery 2 hrs to die ..thus clearing the ram(it holds the last setup info when you shut the crane down for lunch then restart it) ..Hence maybe why she came up clear the next morning..
The Battery in the ones that I opened up(you have to bust the security seal's) ..the big grey box..the battery is on the bottom of the board..with solder lugs right to the board..Ni-cad cell ..newer units may be running a Lipo or Nimh battery..They do go sour after a time..and can cause trouble
Just so you know I busted the seals to get the resistor to get past the A2B because the cable broke on the reel..There are also a few spare fuse's in there as well..boom length is whacked but and weights are wrong ..but its gets a guy going

Another thing i had issues with were cell phone booster stations ..sometimes at peak hrs the things would run my LMI a little silly..but that's rare ,rare...and
rare some more..atmospheric conditions ,boom length ,crane position ..amongst other things ,all had to line up ..and when it did there was always a booster station within a few miles radius..

our Electronics guy would look at it after it happened more than a couple times a week..at that point there is a problem

Circuit boards, Potentiometers don't magically heal ,it works or it doesn't..

In the case of Pot's..as soon as you hit that sweet spot it'll go stupid..
Boards..you'll almost be able to set your watch to it as they warm up..

Oxidation on components ..Intermittent screw up's can often be a simple loose wire ..

I have had similar situations as yours on other machines the EKS Krupp systems,Greer,EKOS on Grove..
the Liccon and Demag systems are pretty solid

 

[Impact]

Thanks for the input guys. Sounds like I should just "let it be" for now. It may need a reboot button like a PC running MS windows. Whenever all else fails, reboot.

 

[liebherr1160]

Thanks for the input guys. Sounds like I should just "let it be" for now. It may need a reboot button like a PC running MS windows. Whenever all else fails, reboot.

In that..the reset button would be a normally on micro switch to kill the power from the board battery when the crane is shut down and the battery master is turned off..

That would clear and reset the LMI to a fresh start..Parts would be under 20$ at a electronincs store,
new rechargable battery,battery holder,18ga wire,micro switch (5A normally on mometary off,SPST),
3/32 drill bit, 1/4 open end wrench,25/35 watt soldering iron,wrist bonding strap..(any braded wire loom ..and some spring clamps)

But lets not get carried away:drinkup

 

[Impact]

Finally had to call someone with more tools than a sledge hammer and vice grips. Come to find out the angle transducer was stuck. I hate it whenever than happens.

 

[liebherr1160]

Finally had to call someone with more tools than a sledge hammer and vice grips. Come to find out the angle transducer was stuck. I hate it whenever than happens.

That makes for a bad day...

 

[willie59]

That makes for a bad day...

Naw naw...that's a good day! Impact had the wisdom to recognize that some jobs just aren't suited for sledge and vice grips.