Continuing the discussion from Z axis & Motor Calibration:
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fantastic. I’ll poke at this.
one thing that would be great to do would be to have three sections (possiibly three tabs, possibly on the same tab), the first two the same as you have now, the third showing the difference in force between the first two
here’s a version that lets you see the differences that changes make
https://docs.google.com/spreadsheets/d/1mv-sUyig7rTph58ell1ETJP32yo1pq4JgaVvp45PKqU/
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@dlang, Do you need to grant permission for us to access this version of the spreadsheet?
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yes I did, try again
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…
hmm,can we add expected chain sag to this?
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anyone who wants edit access, let me know. I don’t want to give edit access to the world, but I’m very willing to give it to anyone who asks
tweaked to make the fill yellow if force > 50 pounds and red if > 60
could an admin please take the posts from 19 on and make a new topic to cover this spreadsheet?
Sample Values
| Stock | ||||
|---|---|---|---|---|
| motorSep | 116.00 | in | min force | 3.26 |
| motorHt | 18.00 | in | max force | 33.74 |
| workAreaWidth | 96.00 | in | min angle | 9.64 |
| workAreaHt | 48.00 | in | max angle | 81.38 |
| sledWeight | 20.00 | lb |
| 12’ top beam | |||
|---|---|---|---|
| motorSep | 140.00 in | min force | 6.44 |
| motorHt | 18.00 in | max force | 40.15 |
| workAreaWidth | 96.00 in | min angle | 8.67 |
| workAreaHt | 48.00 in | max angle | 71.57 |
| sledWeight | 20.00 lb |
| 12" motorHt | |||
|---|---|---|---|
| motorSep | 116.00 in | min force | 3.50 |
| motorHt | 12.00 in | max force | 49.36 |
| workAreaWidth | 96.00 in | min angle | 6.46 |
| workAreaHt | 48.00 in | max angle | 80.54 |
| sledWeight | 20.00 lb |
| 30 lb sled | |||
|---|---|---|---|
| motorSep | 116.00 in | min force | 4.89 |
| motorHt | 18.00 in | max force | 50.61 |
| workAreaWidth | 96.00 in | min angle | 9.64 |
| workAreaHt | 48.00 in | max angle | 81.38 |
| sledWeight | 30.00 lb |
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@jwolter thinking about combining the two spreadsheets.
I removed 3 of the 9 points of measurements because the forces are just mirrors of the points on the other side. Do you think that’s reasonable? or should we keep them?
I removed them in an attempt to fit everything critical on one screen, but that is highly dependent on the screen space you have available.
@dlang go for it!
As people contemplate wider and higher motor mounts, I think it would be good to incorporate chain weight into the calculations. I’m not sure chain weight is important, but it’s not that difficult to add. Anyone know off-hand how much the chains weigh per unit length?
I’ll reply to my own question. According to this definitive informations source (https://www.amazon.com/Roller-Chain-Connector-Connecting-Replacements/dp/B071LBXW5L) carbon steel #25 chain weighs 0,15 kg/m, or 0.10 lbm/ft for those of us using stubborn units. So we need 10 ft of chain to add a pound of weight to the load the motors need to carry. Not completely insignificant, but a second-order effect. I still might add it to the calculations for good measure.
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chain weight is handled in the calibration, so we don’t need it in the
spreadsheet
ahh, I wasn’t thinking in terms of the weight for the motors. I figure the sled
weight is only accurate within a couple pounds anyway
On the other hand, chain weight may become relevant when Bar and Hannah release the ruggedized Maslow.
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Yes, I’ve heard the rumours about them negotiating with china to paint the Chinese Wall with a Maslow mounted to a bus 
.
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This looks like this might be helpful. I don’t know python, but looks well explained for calculating hang plotter line tension.
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