This is a page to track lenslet mask performance issues and the steps we take to troubleshoot. So far the lenslet mask performance has become more unreliable. Due to the lack of encoders, there is no feedback to track which lenslet mask position is really in use. The unreliable behavior has made it more difficult and time consuming to make rectification matrices.

Default lenslet mechanism setting:

• speed = 300 steps/s

• acceleration = 200 steps/s/s

• homing speed = 400 steps/s

A few things to try to troubleshoo

• Try reduce speed to 200 steps/s
  – scans looked bad, spotty.
• Try reduce acceleration
• Try changing om4s homing speed
• om4s homing speed is 400 steps/s, try increasing speed up to 400 steps/s
  – scans looked bad, spotty.
• Try moving between narrowband and broadband and see if it is reliable
  – stage arrived to narrow band correctly but appeared lost in OSGUI
  – stage arrived to broad band correctly
• Move between Broad and Narrow in steps. Go to an intermediate location (stage will be lost), drive in steps the known amount and see if the switch is triggered (stage will no longer be lost)
  – stage remained lost the whole time. arrive to some locations 1 step short or 1 step too far, arrived to some locations correctly.
  – this is seen in both directions
• Check whether scan_number locations are defined correctly
  From stepped scans, a new slope is determined (named locations vs. flux peaks), and named location values are updated.
  Now recmat scans are normal again.
• Step the mask across all the lenslets in even steps.
  – mask stage was suck at Scan 2, no light.
  – with every 10 steps and every 6 steps. Uneven illumination, plots in 200616 scans page.
• Reverse scan direction
  – Saw no light at all. ofls is running on napili. 
  Very low flux in the first 1/3 of the scans when scan direction is reversed. When going the default direction, fluxe drops in the last 1/3 of the scans. om4s stage is slanted at 45 deg, and the default scan direction is “going up”. The physical top 1/3 of the scan positions in om4s stage is problematic.
  

Problematic recmat scan symptoms:

• After about 100 scans (in narrowbands) lenslet fluxes drop significantly and become uneven

• Uneven lenslet fluxes in every scan