Cannot get successful Cal

Troubleshooting
1

Version 1.04
anchor points 2416.75mm x 2952.75mm
4x8 foot cutting area
Config Setup
Extend Dist 1900.000
Orientation Vertical
Calibration Grid
Width(mm) 500.000
Height(mm) 300.000
Grid Size:3x3
Retraction Force 1300
Calibration Force 1300

After Cal
[MSG:INFO: Measured waypoint 88]
CLBM:[{bl:1757.65, br:1942.56, tr:2052.72, tl:2051.01},{bl:1856.51, br:1879.91, tr:1959.95, tl:2149.37},{bl:1976.94, br:1785.82, tr:1844.96, tl:2051.49},{bl:1875.52, br:1975.23, tr:1939.49, tl:1944.42},{bl:1739.53, br:1973.39, tr:2046.73, tl:1842.63},{bl:1627.07, br:1886.40, tr:2151.48, tl:1951.45},{bl:1857.17, br:1877.81, tr:1915.05, tl:1918.74},{bl:1787.62, br:1800.34, tr:1995.14, tl:2004.51},{bl:1600.14, br:1993.31, tr:2171.79, tl:1850.49},{bl:1682.65, br:2064.03, tr:2095.99, tl:1753.26},{bl:1779.33, br:2140.13, tr:2017.46, tl:1658.65},{bl:1948.58, br:1966.55, tr:1826.00, tl:1828.78},{bl:2126.98, br:1793.13, tr:1649.07, tl:2021.45},{bl:2050.58, br:1699.28, tr:1736.96, tl:2100.15},{bl:1979.85, br:1609.98, tr:1835.33, tl:2182.27},{bl:1910.51, br:1533.63, tr:1936.86, tl:2268.28},{bl:1711.06, br:1729.29, tr:2089.52, tl:2104.75},{bl:1518.56, br:1930.04, tr:2258.51, tl:1951.53},{bl:1333.62, br:2135.32, tr:2441.39, tl:1819.94},{bl:1416.77, br:2192.21, tr:2368.43, tl:1712.93},{bl:1515.49, br:2256.30, tr:2292.45, tl:1606.23},{bl:1620.68, br:2326.58, tr:2220.84, tl:1502.33},{bl:1730.50, br:2405.84, tr:2154.29, tl:1401.92},{bl:1882.48, br:2232.00, tr:1945.21, tl:1561.39},{bl:2043.61, br:2059.28, tr:1744.75, tl:1747.68},{bl:2213.48, br:1894.34, tr:1558.60, tl:1948.31},{bl:2385.73, br:1738.59, tr:1392.71, tl:2159.24},{bl:2312.94, br:1630.78, tr:1486.39, tl:2226.87},{bl:2238.66, br:1529.03, tr:1590.54, tl:2297.67},{bl:2174.00, br:1432.49, tr:1697.47, tl:2372.97},{bl:2095.14, br:1383.32, tr:1806.78, tl:2452.31},{bl:2061.28, br:1262.38, tr:1917.94, tl:2535.40},{bl:1853.59, br:1457.15, tr:2042.51, tl:2364.77},{bl:1649.62, br:1656.61, tr:2186.52, tl:2201.29},{bl:1448.47, br:1868.10, tr:2348.58, tl:2055.23},{bl:1253.61, br:2082.57, tr:2524.98, tl:1930.75},{bl:1067.73, br:2302.58, tr:2712.98, tl:1832.01},{bl:1153.78, br:2345.12, tr:2642.26, tl:1717.74},{bl:1255.04, br:2395.50, tr:2568.31, tl:1601.62},{bl:1362.56, br:2454.42, tr:2498.39, tl:1486.88},{bl:1475.01, br:2554.50, tr:2433.01, tl:1373.89},{bl:1592.65, br:2584.38, tr:2372.20, tl:1263.46},{bl:1714.35, br:2659.88, tr:2316.69, tl:1155.92},{bl:1847.89, br:2495.16, tr:2095.16, tl:1298.84},{bl:1993.80, br:2325.18, tr:1877.43, tl:1476.02},{bl:2148.81, br:2160.84, tr:1668.75, tl:1671.92},{bl:2309.83, br:2002.38, tr:1473.14, tl:1880.70},{bl:2473.05, br:1852.89, tr:1296.36, tl:2098.43},{bl:2643.82, br:1713.01, tr:1147.10, tl:2322.66},{bl:2569.51, br:1594.28, tr:1248.31, tl:2379.86},{bl:2497.63, br:1478.34, tr:1359.23, tl:2439.85},{bl:2430.57, br:1366.39, tr:1472.44, tl:2504.68},{bl:2371.48, br:1260.99, tr:1587.36, tl:2573.91},{bl:2319.37, br:1163.19, tr:1703.66, tl:2647.28},{bl:2271.76, br:1074.52, tr:1821.13, tl:2724.37},{bl:2231.47, br:991.92, tr:1939.51, tl:2804.91},{bl:2016.42, br:1188.91, tr:2033.15, tl:2628.76},{bl:1803.80, br:1444.77, tr:2149.32, tl:2457.39},{bl:1628.32, br:1588.39, tr:2286.40, tl:2300.47},{bl:1411.71, br:1806.58, tr:2442.18, tl:2161.15},{bl:1211.42, br:2018.35, tr:2612.04, tl:2043.02},{bl:1022.84, br:2230.05, tr:2794.07, tl:1950.04},{bl:843.31, br:2443.32, tr:2986.04, tl:1885.93},{bl:937.88, br:2475.50, tr:2917.19, tl:1767.24},{bl:1037.94, br:2519.89, tr:2844.87, tl:1645.18},{bl:1148.62, br:2567.17, tr:2776.31, tl:1523.60},{bl:1262.78, br:2619.25, tr:2711.77, tl:1402.57},{bl:1381.58, br:2678.06, tr:2651.55, tl:1282.29},{bl:1504.90, br:2745.33, tr:2595.96, tl:1162.89},{bl:1631.80, br:2815.95, tr:2545.31, tl:1044.99},{bl:1763.33, br:2894.51, tr:2499.90, tl:928.84},{bl:1894.62, br:2746.92, tr:2269.45, tl:1045.13},{bl:2018.34, br:2593.73, tr:2040.27, tl:1208.14},{bl:2143.00, br:2433.50, tr:1829.32, tl:1396.90},{bl:2278.84, br:2280.14, tr:1619.76, tl:1602.55},{bl:2443.76, br:2138.37, tr:1405.68, tl:1819.27},{bl:2613.97, br:2008.99, tr:1205.32, tl:2043.47},{bl:2771.62, br:1880.78, tr:1042.90, tl:2273.10},{bl:2927.27, br:1754.36, tr:921.02, tl:2506.58},{bl:2855.32, br:1624.27, tr:1031.09, tl:2554.34},{bl:2786.03, br:1495.62, tr:1149.36, tl:2604.35},{bl:2718.01, br:1371.59, tr:1269.07, tl:2659.30},{bl:2659.84, br:1250.44, tr:1389.62, tl:2718.90},{bl:2606.29, br:1134.95, tr:1510.77, tl:2782.82},{bl:2559.63, br:1021.85, tr:1632.64, tl:2850.80},{bl:2517.46, br:915.22, tr:1754.88, tl:2922.55},{bl:2479.62, br:819.50, tr:1877.50, tl:2997.80},{bl:1633.20, br:1591.39, tr:2285.47, tl:2293.60},{bl:1901.72, br:1872.19, tr:1911.86, tl:1921.87},]
Computing… This may take several minutes
[MSG:INFO: Requesting state change from Calibrating to Ready To Cut]Fitness: 0.0642175 in 1700
Fitness: 0.0642219 in 1800
Fitness: 0.0636386 in 100
Fitness: 0.0642250 in 1900
Fitness: 0.0636386 in 200
Fitness: 0.0642277 in 2000
Fitness: 0.0638164 in 300
Fitness: 0.0642296 in 2100
Fitness: 0.0640021 in 400
Fitness: 0.0642311 in 2200

JogTo: '$J=G91F2500X-100
'Fitness: 0.0641368 in 500
Fitness: 0.0642323 in 2300
Fitness: 0.0642447 in 600
Fitness: 0.0642332 in 2400
Fitness: 0.0643257 in 700
Fitness: 0.0642339 in 2500
Fitness: 0.0643871 in 800
Fitness: 0.0642344 in 2600
Fitness: 0.0644385 in 900
Fitness: 0.0642349 in 2700
Fitness: 0.0644758 in 1000
Fitness: 0.0642352 in 2800
Fitness: 0.0645054 in 1100
Fitness: 0.0642355 in 2900
Fitness: 0.0645287 in 1200
Fitness: 0.0642357 in 3000
Fitness: 0.0645479 in 1300
Fitness: 0.0642358 in 3100
Fitness: 0.0645625 in 1400
Fitness: 0.0642360 in 3200
Fitness: 0.0645732 in 1500
Fitness: 0.0642361 in 3300
Fitness: 0.0645816 in 1600
Fitness: 0.0642361 in 3400
Fitness: 0.0645890 in 1700
Fitness: 0.0642362 in 3500
Fitness: 0.0645941 in 1800
Fitness: 0.0642362 in 3600
Fitness: 0.0645986 in 1900
Fitness: 0.0642362 in 3700
Fitness: 0.0646019 in 2000
Fitness: 0.0642363 in 3800
Fitness: 0.0646047 in 2100
Fitness: 0.0642363 in 3900
Fitness: 0.0646067 in 2200
Fitness: 0.0642363 in 4000
Fitness: 0.0646084 in 2300
Fitness: 0.0642363 in 4100
Fitness: 0.0646097 in 2400
Fitness: 0.0642363 in 4200
Fitness: 0.0646107 in 2500
Fitness: 0.0642363 in 4300
Fitness: 0.0646115 in 2600
Fitness: 0.0642363 in 4400
Fitness: 0.0646121 in 2700
Fitness: 0.0642363 in 4500
Fitness: 0.0646126 in 2800
Fitness: 0.0642363 in 4600
Fitness: 0.0646130 in 2900
Fitness: 0.0642363 in 4700
Fitness: 0.0646133 in 3000
Fitness: 0.0642363 in 4800
Fitness: 0.0646135 in 3100
Fitness: 0.0642363 in 4900
Fitness: 0.0646137 in 3200
Fitness: 0.0642363 in 5000
Fitness: 0.0646139 in 3300
Fitness: 0.0642363 in 5100
Fitness: 0.0646140 in 3400
Fitness: 0.0642363 in 5200
Fitness: 0.0646141 in 3500
Fitness: 0.0642363 in 5300
Fitness: 0.0646142 in 3600
Fitness: 0.0642363 in 5400
Fitness: 0.0646142 in 3700
Fitness: 0.0642363 in 5500
Fitness: 0.0646143 in 3800
Fitness: 0.0642363 in 5600
Fitness: 0.0646143 in 3900

Calculated Fitness Too Low. The process will automatically try again.!
Calibration values:
Fitness: 0.06423633709811372
Maslow_tlX: -12.8
Maslow_tlY: 2360.8
Maslow_trX: 2943.6
Maslow_trY: 2384.2
Maslow_blX: 0.0
Maslow_blY: 0.0
Maslow_brX: 2973.9
Maslow_brY: 0.0
RestartingFitness: 0.0646143 in 4000
Fitness: 0.0634512 in 100

1 Like
2

It looks like you’ve got mostly good data with a couple funky measurements in there which are throwing things off

image
image1272×854 147 KB

Could a belt have gotten caught on something leading to a funky measurement at some point?

A 3x3 grid should only be using 9 points so there is something funny going on there too.

3

Belt not catching. Hold slight tension on belt during calibration process. Config settings very confusing. It would be nice to understand logic behind them.
I do finally get cal to work, but have no idea what I did differently

1 Like
4

TerryTaul wrote:

Belt not catching. Hold slight tension on belt during calibration process.
Config settings very confusing. It would be nice to understand logic behind
them.

alibration could be renamed “calculate where the anchors are”

it starts off with a guess on the frame size (based on pullting the belts tight
at what should be close to the center, but the exact location doesn’t matter
much)

Then it moves through a grid (3x3 or other) within the assigned area
(calibration size), moving a bit and pulling the belts tight. At this point it’s
gathering data points of what sevethe belt lengths are at several points

Then it uploads this to the browser, which runs a bunch of calculations to try
and figure out what the anchor coordinates could be to produce this combination
of belt lengths.

the more points, and the more of the work area they cover, the harder it is to
get a good set of anchor coordinates (but the more accurate those coordinates
are likely to be)

If the belts are slack or not in direct line to the arms (say the arms hit the
uprights and can’t swivel) then you have bad data points in the caclulation (as
Bar noted for your initial post, and that can throw off the calculations

the fitness score is 1/error where error is the difference between the
calculated anchor points and where the belts would actually end up for the test
points.

hope this helps a bit.

David Lang

1 Like
5

I’m sorry David, this doesn’t help me much. I would like to know exactly what the config values should be. The horizontal or vertical option does not make sense. What is the value there for? What is the proper calibration grid size?
I have done many calibrations and have had several successful calibrations, but when i move the sled to the bottom corner, a couple of the belts go slack before getting there, then when i try to run g-code it locks the machine immediately.
What are the right fitness values?

Thank you for the help,
Terry

6

TerryTaul wrote:

I’m sorry David, this doesn’t help me much. I would like to know exactly what
the config values should be.

The horizontal or vertical option does not make sense. What is the value there
for?

is the frame vertical (like a wall) or horizontal (like a floor)? if it’s
vertical, the sled is hanging from two belts and all movement needs to account
for that. If it’s horizontal on the floor, it can’t count on gravity to keep the
top two belts tight.

What is the proper calibration grid size?

the bigger and more points, the better, except if you have it too big for your
frame you end up measuring the belt length at places where the belt isn’t
straight and that throws off the calibration calculations.

what is your frame size?

I have done many calibrations and have had several successful calibrations

what fitness scores are you getting?

but when i move the sled to the bottom corner, a couple of the belts go slack
before getting there, then when i try to run g-code it locks the machine
immediately. What are the right fitness values?

the higher the fitness score the better. By default, it won’t accept a fitness
less than 0.45

David Lang

7

David,

This is driving me nuts! I do retract, extend, start cal. Looks good at first, then belts get way too tight and start clicking.

Setup
Vertical setup 4x8’ cutting
Frame anchor points w=2952.75mm, h=2416.175
Ext dist 1800
Cal grid w=2000, h=1000 9x9
Force =1300 both
Passed cal, but fitness says .05-.105 in xxx

8

Similar situation to TerryTaul.
M4 appears to be locating itself ‘in the wrong place’, i.e.:

  • After Retract/Extend/Apply tension it’s located in the BOTTOM center of the work area
  • Subsequently, the Ground Control panel often shows a location where Y is a NEGATIVE number (eg -744; Isnt bottom left pin the origin, i.e. 0/0? In which case how are Y coordinate negative?)
  • Calibration systematically produces tiny numbers and never stops - see Serial Log below.

I might be wrong but far as I can tell, this behavior is new - and started to occur (in addition to a non-responsive tool; which I’ve been able to usually overcome, by reloading the Ground Control browser) only after the recent update to V1.02 (prior to which Ive been on a version less than 1.0)
Am I completely misunderstanding the coordinate system - perhaps including the way I had entered the tlX, tlY etc values under FluidNC Settings??!?
(my entries: blX and blY are 0,0; and trX and trY are 3504, 2504 etc)

Serial log:
Retract All
[MSG:INFO: Retracting all belts]
[MSG:INFO: Requesting state change from 0 to 1]
[MSG:INFO: Bottom Right pulled tight with offset -1164.565]
[MSG:INFO: Top Right pulled tight with offset -1756.434]
[MSG:INFO: Bottom Left pulled tight with offset -2480.529]
[MSG:INFO: Top Left pulled tight with offset -2832.050]
[MSG:INFO: Requesting state change from 1 to 2]
Extend All
[MSG:INFO: Extending all belts]
[MSG:INFO: Requesting state change from 2 to 3]
[MSG:INFO: All belts extended to 2500.000mm]
[MSG:INFO: Requesting state change from 3 to 4]
Apply Tension
[MSG:INFO: Requesting state change from 4 to 5]
[MSG:ERR: Measurement error, measurements are not within 2.5 mm of each other, trying again]
[MSG:INFO: Max deviation: 175.510]
[MSG:INFO: Bottom Right 2650.093]
[MSG:INFO: Bottom Right 2650.082]
[MSG:INFO: Bottom Right 2650.082]
[MSG:INFO: Bottom Right 2650.082]
[MSG:INFO: Top Right 2630.044]
[MSG:INFO: Top Right 2632.526]
[MSG:INFO: Top Right 2632.526]
[MSG:INFO: Top Right 2808.036]
[MSG:INFO: Top Left 1980.184]
[MSG:INFO: Top Left 1980.184]
[MSG:INFO: Top Left 1980.184]
[MSG:INFO: Top Left 1980.184]
[MSG:INFO: Bottom Left 1708.238]
[MSG:INFO: Bottom Left 1708.432]
[MSG:INFO: Bottom Left 1708.475]
[MSG:INFO: Bottom Left 1708.496]
[MSG:ERR: Measurement error, measurements are not within 2.5 mm of each other, trying again]
[MSG:INFO: Max deviation: 8.897]
[MSG:INFO: Bottom Right 2650.050]
[MSG:INFO: Bottom Right 2650.104]
[MSG:INFO: Bottom Right 2650.114]
[MSG:INFO: Bottom Right 2650.125]
[MSG:INFO: Top Right 2651.801]
[MSG:INFO: Top Right 2651.769]
[MSG:INFO: Top Right 2651.801]
[MSG:INFO: Top Right 2651.791]
[MSG:INFO: Top Left 1980.087]
[MSG:INFO: Top Left 1971.190]
[MSG:INFO: Top Left 1970.911]
[MSG:INFO: Top Left 1970.911]
[MSG:INFO: Bottom Left 1710.014]
[MSG:INFO: Bottom Left 1710.574]
[MSG:INFO: Bottom Left 1710.833]
[MSG:INFO: Bottom Left 1710.962]
[MSG:INFO: Measured waypoint 2]
[MSG:INFO: Center point deviation: TL: 0.000 TR: 0.000 BL: 129.090 BR: -107.382]
[MSG:ERR: Center point deviation over 12.000mm, your coordinate system is not accurate, maybe try running calibration again?]
[MSG:INFO: Requesting state change from 5 to 4]
JogTo: '$J=G91F2500Y100
’
Calibrate
[MSG:INFO: Requesting state change from 4 to 6]
[MSG:INFO: Setting z-stop position]
[MSG:INFO: Machine Position found as X: 8.875 Y: -746.362]
[MSG:ERR: Measurement error, measurements are not within 2.5 mm of each other, trying again]
[MSG:INFO: Max deviation: 41.073]
[MSG:INFO: Bottom Right 2554.215]
[MSG:INFO: Bottom Right 2538.179]
[MSG:INFO: Bottom Right 2529.434]
[MSG:INFO: Bottom Right 2522.142]
[MSG:INFO: Top Right 2385.558]
[MSG:INFO: Top Right 2344.486]
[MSG:INFO: Top Right 2313.911]
[MSG:INFO: Top Right 2286.699]
[MSG:INFO: Top Left 1977.208]
[MSG:INFO: Top Left 2007.498]
[MSG:INFO: Top Left 2031.781]
[MSG:INFO: Top Left 2053.710]
[MSG:INFO: Bottom Left 1768.028]
[MSG:INFO: Bottom Left 1772.237]
[MSG:INFO: Bottom Left 1773.389]
[MSG:INFO: Bottom Left 1773.507]
[MSG:ERR: Measurement error, measurements are not within 2.5 mm of each other, trying again]
[MSG:INFO: Max deviation: 23.807]
[MSG:INFO: Bottom Right 2506.642]
[MSG:INFO: Bottom Right 2502.652]
[MSG:INFO: Bottom Right 2502.533]
[MSG:INFO: Bottom Right 2502.437]
[MSG:INFO: Top Right 2219.506]
[MSG:INFO: Top Right 2195.699]
[MSG:INFO: Top Right 2181.833]
[MSG:INFO: Top Right 2168.635]
[MSG:INFO: Top Left 2112.234]
[MSG:INFO: Top Left 2131.734]
[MSG:INFO: Top Left 2144.766]
[MSG:INFO: Top Left 2158.153]
[MSG:INFO: Bottom Left 1773.830]
[MSG:INFO: Bottom Left 1773.895]
[MSG:INFO: Bottom Left 1773.820]
[MSG:INFO: Bottom Left 1773.733]
[MSG:ERR: Measurement error, measurements are not within 2.5 mm of each other, trying again]
[MSG:INFO: Max deviation: 13.429]
[MSG:INFO: Bottom Right 2492.982]
[MSG:INFO: Bottom Right 2492.949]
[MSG:INFO: Bottom Right 2492.928]
[MSG:INFO: Bottom Right 2492.896]
[MSG:INFO: Top Right 2132.541]
[MSG:INFO: Top Right 2120.104]
[MSG:INFO: Top Right 2109.698]
[MSG:INFO: Top Right 2097.358]
[MSG:INFO: Top Left 2187.504]
[MSG:INFO: Top Left 2200.933]
[MSG:INFO: Top Left 2211.150]
[MSG:INFO: Top Left 2222.828]
[MSG:INFO: Bottom Left 1773.927]
[MSG:INFO: Bottom Left 1773.884]
[MSG:INFO: Bottom Left 1773.863]
[MSG:INFO: Bottom Left 1773.830]
[MSG:INFO: Measured waypoint 0]
[MSG:INFO: Center point off by: TL: 0.000 TR: 0.000 BL: -27.582 BR: -40.439]
[MSG:INFO: Machine Position computed as X: 259.460 Y: -220.570]
[MSG:INFO: Measuring Frame Flex]
[MSG:INFO: Flex measurement: TLBR: 0.164 TRBL: 0.005]
[MSG:INFO: Measured waypoint 1]
[MSG:INFO: Measured waypoint 2]
[MSG:INFO: Measured waypoint 3]
[MSG:INFO: Measured waypoint 4]
[MSG:INFO: Measured waypoint 5]
CLBM:[{bl:2232.93, br:1773.78, tr:2096.70, tl:2492.88},{bl:2361.48, br:1795.80, tr:1996.42, tl:2611.29},{bl:2432.35, br:1762.93, tr:1888.44, tl:2536.61},{bl:2305.98, br:1874.77, tr:1990.94, tl:2411.58},{bl:2176.53, br:1995.47, tr:2105.31, tl:2287.67},{bl:2101.94, br:1919.14, tr:2202.96, tl:2370.59},]
Computing… This may take several minutes
[MSG:INFO: Requesting state change from 6 to 7]Fitness: 0.0250528 in 100
Fitness: 0.0337812 in 200
Fitness: 0.0359721 in 300
Fitness: 0.0365783 in 400
Fitness: 0.0367072 in 500
Fitness: 0.0367072 in 600

etc etc with similar Fitness scores

9

Noamcee wrote:

M4 appears to be locating itself ‘in the wrong place’, i.e.:

  • After Retract/Extend/Apply tension it’s located in the BOTTOM center of the work area
  • Subsequently, the Ground Control panel often shows a location where Y is a NEGATIVE number (eg -744; Isnt bottom left pin the origin, i.e. 0/0? In which case how are Y coordinate negative?)

0,0 is the center of the workspace, not the bottom corner

  • Calibration systematically produces tiny numbers and never stops - see Serial Log below.

I might be wrong but far as I can tell, this behavior is new - and started to occur (in addition to a non-responsive tool; which I’ve been able to usually overcome, by reloading the Ground Control browser) only after the recent update to V1.02 (prior to which Ive been on a version less than 1.0)
Am I completely misunderstanding the coordinate system - perhaps including the way I had entered the tlX, tlY etc values under FluidNC Settings??!?
(my entries: blX and blY are 0,0; and trX and trY are 3504, 2504 etc)

Serial log:
Retract All
[MSG:INFO: Retracting all belts]
[MSG:INFO: Requesting state change from 0 to 1]
[MSG:INFO: Bottom Right pulled tight with offset -1164.565]
[MSG:INFO: Top Right pulled tight with offset -1756.434]
[MSG:INFO: Bottom Left pulled tight with offset -2480.529]
[MSG:INFO: Top Left pulled tight with offset -2832.050]
[MSG:INFO: Requesting state change from 1 to 2]

retract all needs to be with the belts detached, is this the case? (a video
could help)

is the frame vertical (like a wall) or horizontal (like a floor)?

Extend All
[MSG:INFO: Extending all belts]
[MSG:INFO: Requesting state change from 2 to 3]
[MSG:INFO: All belts extended to 2500.000mm]
[MSG:INFO: Requesting state change from 3 to 4]
Apply Tension
[MSG:INFO: Requesting state change from 4 to 5]
[MSG:ERR: Measurement error, measurements are not within 2.5 mm of each other, trying again]

try setting the extended belt length to something a little closer to the middle.

I would guess that you have a vertical frame and are feeding out too much, so
when it’s applying tension, it’s pulling in more slack from the bottom than from
the top where the weight is pulling on it.

from the numbers below, it looks like instead of feeding out 2500 try 2250 or
2300

when you start calibration, make sure the router is all the way down

David Lang

1 Like
10

Ok thanks @dlang , this might be helpful!
Specifically:

  • Yes, was extending 2500. Will reduce as proposed
  • So, 0,0 in center - Fine, solves one bit of my confusion; but fyi - under FluidNC Settings, 0,0 is o bottom left pin (correct?) - Hence a source of confusion.
  • Yes, retract was performed w belts detached
  • My frame is indeed vertical

Thank you!!!

11

Noamcee wrote:

  • So, 0,0 in center - Fine, solves one bit of my confusion; but fyi - under FluidNC Settings, 0,0 is o bottom left pin (correct?) - Hence a source of confusion.

that may just be their default on the display. no matter where you enter
coordinates, they will be based off of the center (until you change where home
is and they will then be based off of that), allowing both positive and negative
numbers

  • Yes, retract was performed w belts detached

ok, I was noting the very high offsets, so that must have been after a power
cycle with the belts long.

it’s useful to do a couple extend/retract cycles and confirm that after the
first retract, future retracts all report very low offsets (near zero, generally
well under 1mm)

David Lang

12

I did get a successful cal, but fitness score was not much above 0.45. i am trying to get sled to bottom left of 4x8 sheet, but before it reached the corner the sled, it was pulling so hard that the bottom is lifting up from the force and it seemed like the belts were about to break, so i hit estop.
I saw somewhere in the forum that offset values should be zero. does that look at the difference between the amount extended then retracted? how do i test for that?
Could the magnet be slipping and causing the belts to get out of wack?

13

TerryTaul wrote:

I saw somewhere in the forum that offset values should be zero. does that look at the difference between the amount extended then retracted? how do i test for that?

yes, every time you do a retract-all it reports what it thinks the belt length
is when it stops moving.

So if you do a retract-all to get to a known state, then an extend-all followed
by a retract-all, the offsets that are reported at the end of the retraction
should be near zero (usually <1mm, possibly <0.1mm). If they are several mm or
larger, then you probably have a magnet in the wrong place or the magnet is
slipping

David Lang

14

This doesn’t sound good. That shouldn’t be happening. Can you get a video of that? Something is wrong there for sure.