v1 STAR.head96: the dispensing drive defaults are checked attributes, no longer queried from the device

[BioCam]

The Problem

The 96-head's default dispensing drive speed and acceleration were wrong in three ways:

• Wrong source. At setup they were taken directly from a firmware query of the device
  (H0RAradv, H0RAradr). That query does not return a default: it returns what the last command
  set. A run that ended on a 10 uL/s dispense left every later session with 10 uL/s as its
  "default", and the piston move before each tip pick-up took 21 s.
• Wrong place. They lived in Head96Configuration. A configuration holds facts about the
  device; a default is what the driver chooses to send, and belongs on the feature (P18).
• Not settable. They were read-only properties, changeable only by overwriting a
  _firmware_reported field.

PR Content/Solution

• Head96.default_dispensing_drive_speed (250 uL/s) and
  Head96.default_dispensing_drive_acceleration (17000 uL/s2; 2900 uL/s2 on a head with firmware
  from before 2010, set at setup from the firmware year).
• The piston move and the head's own aspirate and dispense (H0) take these when given no speed
  or flow rate, so a value is checked against the drive's range when it is assigned:
  star.head96.default_dispensing_drive_speed = 5000.0 raises
  default_dispensing_drive_speed must be between 0.1 and 1063.75, is 5000.0.
• Setup no longer queries the device for dv and dr.
• Head96Configuration loses the two dispensing _firmware_reported fields and _default
  properties, and their keys are dropped from the three recordings.
• The defaults move from 261.1 to 250 uL/s and from 17406.84 to 17000 uL/s2, so the piston move
  sends dv12926 and dr878965 instead of dv13500 and dr900000.

Only the dispensing drive changes; the squeezer, Y and Z drive defaults are as before.

🤖 Generated with Claude Code