Weight tracking with temperature

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wwfoste
Weight tracking with temperature

I'd posted this in my rain post, but this is really a separate question. My scale has started tracking parallel with the ambient temperature. I have the frameless design. I believe this indicates that the end of the bolt of the leveling foot is touching the strut and the heat up and cool down of the strut is governing the weight changes. I'm thinking of just backing the foot back and not worrying with any overload protection. Before I go through the effort of taking the hive off and fixing the feet, I was just going to see if anyone else had run into this or had a different idea of the issue.

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Nate
Nate's picture
Overload Protection

Overload settings according to the wiki are .002 inches - Is that what you used? that's what I'm setting mine at for right now anyway.

There isn't much space for .002 inches - a piece of dust, dirt or whatever could get in there and cause problems, the metal may have fatigued a little, how about taking your feeler gauge out there and just make sure you do indeed still have the .002" clearance between the bolt and the strut? You may have to rig up a shim to unload each strut before testing... but pretty uninvasive test.

wwfoste
Overload protection

Yes, I set it for 0.002 using a spark plug gauge. I think i'm just going to back it off to where it won't be close and see what it does. Then just be careful putting boxes on.

wwfoste
Appears to be fixed

I backed the level feet off and recalibrated the scale. It seemed to fix the issue.

Paul
Paul's picture
.002 inch overload protection

I have also had problems with the overload protection interfering with normal scale operation. I think the .002 inch deflection was measured with a dial gauge (.0001 inch scale) clamped to the frame and the frame loaded to 400 lbs, but it has been a while since I ran that test.

I no longer set the the overload protection at all and make sure the foot is backed off way out of the way. I have been told that in normal operation, damaging the load cell is unlikely, even if you drop a full super of honey on top of the hive, or push hard on a frame to get it back in place.

Dr. Esaias said the damage to a load cell occurs if you drop the frame off a table and one corner hits a concrete floor. They can also be damaged during shipping if the frame is not properly packed.

The load cells we use are rated at 150% overload (some load cells are only rated at 125% overload). I am sorry if the suggested .002 inch clearance has caused problems. Please keep in mind that this is still in development and we are all experimenting. I do not think we have the ideal frame design yet and I don't know if it is possible to incorporate overload protection in frames that are home made. This will probably require some destructive testing to determine if the overload protection actually works.

As far as I know, no one has damaged load cells so far but that is no guarantee that it can't be done!

wwfoste
Update to Hivetool.org Frame Assembly section

I'd recommend noting this here: http://www.hivetool.org/w/index.php?title=Hardware:_Frame_Assembly#Mount...

At least note that having the leveling leg too close to the strut may result in errant readings.

Adrian
Leveling feet too close to strut - revise instructions

I've altered the instructions to note the concern.

Adrian Ogden

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