# Holey Triangular Calibration

**URL:** https://forums.maslowcnc.com/t/holey-triangular-calibration/6240
**Category:** Technical Details
**Created:** [August 29, 2018, 7:25pm UTC](https://forums.maslowcnc.com/t/holey-triangular-calibration/6240 "2018-08-29T19:25:54Z")
**Posts on this page:** 1
**Showing post:** 95

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### Author: ![dlang](https://yyz1.discourse-cdn.com/flex031/user_avatar/forums.maslowcnc.com/dlang/32/859_2.png) [@dlang](https://forums.maslowcnc.com/u/dlang)
#### Post date: [November 1, 2018, 10:16pm UTC](https://forums.maslowcnc.com/t/holey-triangular-calibration/6240/95 "2018-11-01T22:16:53Z")

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> > [@dlang](#):
> >
> > time to loop their chains and run a series of tests
> 
> Tomorrow is Friday, the lazy day. If the instructions are clear I would invest 3 hours (if that is enough) on Saturday if it helps.  
> I would need to break a chain I guess. Can do that.

connect the chains together using the master links into a loop, put the loop  
over both motors (close to snug, you don’t need to worry about 12 o’clock). clear your log file

```auto
G21 ( metric mode )
G91 (relative mode)
B11 R S-63 T 5 ( run the right motor at a bit under 1/4 power for 5 sec )

( if this doesn't take up the slack, repeat until the slack is taken up)

B06 L0 R0 ( set chain lengths to 0)
B09 L5 ( move the left motor a little bit to release tension )
B09 L95 R-95 ( move to the right about 4 inches, leaving a little slack to take up in the next step )
B11 R S-63 T 5 ( run the right motor at a bit under 1/4 power for 5 sec )
B10 L ( report the position of the left motor )
B10 R ( report the position of the right motor )

B06 L0 R0 ( set chain lengths to 0)
B09 L5 ( move the left motor a little bit to release tension )
B09 L95 R-95 ( move to the right about 4 inches, leaving a little slack to take up in the next step )
B11 R S-63 T 5 ( run the right motor at a bit under 1/4 power for 5 sec )
B10 L ( report the position of the left motor )
B10 R ( report the position of the right motor )

B06 L0 R0 ( set chain lengths to 0)
B09 L5 ( move the left motor a little bit to release tension )
B09 L95 R-95 ( move to the right about 4 inches, leaving a little slack to take up in the next step )
B11 R S-63 T 5 ( run the right motor at a bit under 1/4 power for 5 sec )
B10 L ( report the position of the left motor )
B10 R ( report the position of the right motor )

```

repeat this block until you have finished the loop

what we will be looking for in the log is the lines:  
B10 L  
[Measure: 199.94]  
B10 R  
[Measure: 199.76]

and how much they vary over the loops.

I expect that B10 L is always going to be the same (or _very_ close to it), and  
B10 R is what should vary.

This is only pulling at 1/4 power, if you add a second B11 line with S-255 that  
will run the motor at full power. It would be interesting to have one loop be:

```auto
B06 L0 R0 ( set chain lengths to 0)
B09 L5 ( move the left motor a little bit to release tension )
B09 L95 R-95 ( move to the right about 4 inches )
B11 R S-63 T 5 ( run the right motor at a bit under 1/4 power for 5 sec )
B10 L ( report the position of the left motor )
B10 R ( report the position of the right motor )
B11 R S-255 T 2 ( run the right motor at a bit under 1/4 power for 5 sec )
B10 L ( report the position of the left motor )
B10 R ( report the position of the right motor )

```

and see how much the two positions differ (how much does the extra power reduce  
chain sag and/or stretch the chain)

David Lang

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