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mdcpickandplace:fiducials [2010/06/11 18:59]
ladyada created
mdcpickandplace:fiducials [2016/01/28 18:05] (current)
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 Basically, define a 1mm dot with a 2mm window. you can mess with **Level** but 0.9 seems good to us Basically, define a 1mm dot with a 2mm window. you can mess with **Level** but 0.9 seems good to us
  
-In the parts placement, set one fiducial to **F**ee**d**e**r** #261 and the other to #262+In the PCB parts placement, set one fiducial to **F**ee**d**e**r** #261 and the other to #262
  
 {{:​mdcpickandplace:​drawfid.png|}} {{:​mdcpickandplace:​drawfid.png|}}
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 If you want the fiducials to be checked for each board of a step&​repeat,​ set the **A**ngle to be nonzero - I use '​1'​. If **A**ngle = 0 it will only check the first PCB in the repeat! If you want the fiducials to be checked for each board of a step&​repeat,​ set the **A**ngle to be nonzero - I use '​1'​. If **A**ngle = 0 it will only check the first PCB in the repeat!
  
 +Make sure you set the Bias point first so that you have that correct, we put the fid's as the first two elements in the PCB parts.
 +
 +
 +====== Offsetting ======
 +
 +One problem that may occur with fiducials is the harsh direct light from the top vision may create '​bumps'​ that show up dark, confusing the vision detection. This is due to the solder surface being uneven, the shadows show up particularly well as seen here:
 +
 +{{:​mdcpickandplace:​arduinomark.jpg|}}
 +
 +Try reducing the **Level** to 0.8 or 0.9. If that doesn'​t help, a solution is to program in the fiducial with a detection offset, say 4mm in one direction. This way the light is angled, more diffused:
 +
 +
 +{{:​mdcpickandplace:​arduinomark4mmoffset.jpg|}}
 +
 +Put **4** into the **dx0** column to shift over the vision recognition.
 +
 +^ Part ^ Nozzle ^ dx0 ^ dy0 ^ st ^ da9 ^ X ^ Y ^ Pt ^ W ^ Thick ^ LunaVis ^ TS ^ Level ^ Type ^ Voff ^ Remark ^
 +^ 1mm fiducial | 2 | **4** | 0 | 0 | 0 | 2 | 2 | 0 | 0 | 1 | 1 | 50 | 0.9 | MARK3 | | 1mmfi |
 +
 +{{:​mdcpickandplace:​4mmoffset.jpg|}}
 +
 +You can also try Teach mode, press Shift+S and enter "​3,​2,​2,​1,​0.9,​4"​ for test (MARK3 type mark, 2mm by 2mm window, 1mm dot, 0.9 Level, 4mm offset)
  
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