Mirrors

Table of contents

2-Post Mirror

2postMirror.adl

The 2postMirror.db database provides coordinated motion support for a mirror mounted on two posts (upstream and downstream). The database converts between raw motor positions and four virtual axes:

Virtual Axis Description
Downstream Position of the downstream post motor
Upstream Position of the upstream post motor
Angle Mirror angle in milliradians
Average Average height of the two posts in mm

The database includes tweak controls for each axis, set/use calibration mode, synchronization, and a DMOV (done-moving) PV.

Macros

Macro Description
$(P) PV prefix
$(Q) Mirror instance identifier
$(mUp) Motor record name for the upstream post
$(mDn) Motor record name for the downstream post
$(LENGTH) Distance between the two posts (meters)

Loading the database 

dbLoadRecords("$(OPTICS)/opticsApp/Db/2postMirror.db","P=xxx:,Q=M1:,mUp=m1,mDn=m2,LENGTH=0.5")

ASRP Mirror Table

The ASRP (Advanced Synchrotron Radiation Project) mirror table database provides coupled pitch-angle and vertical-height control. When a desired pitch angle is specified in milliradians, the database calculates and drives the appropriate pitch motor and vertical motor positions to maintain a fixed-point position on the mirror surface.

The geometry is defined by two parameters:

  • pitchArmLen – the distance from the pivot point to the pitch motor
  • fixedPointZ – the distance from the pivot point to the fixed point on the mirror surface

The transform calculations are:

pitch_motor = pitchArmLen * tan(pitch_angle / 1000)
height_diff = fixedPointZ * (new_pitch_motor - current_pitch_motor) / pitchArmLen
new_vert    = current_vert - height_diff

An autosync record monitors the pitch motor via Channel Access and updates the displayed pitch angle whenever the motor is moved externally.

Database variants

Two versions of the ASRP mirror table database are provided:

Database Description
ASRPmirrorTable.db Standard version. Writes the pitch angle directly to the transform record.
ASRPmirrorTable_softmotor.db Adds a soft motor record (coupledPitchAngle) as an intermediate, so the coupled pitch angle can be scanned as if it were a motor. Includes SDIS to prevent mutual triggering between tran and autosync.

Macros

Macro Description
$(P) PV prefix
$(TBL) Mirror table instance identifier
$(PITCH) Pitch motor PV (e.g., xxx:m1)
$(VERT) Vertical motor PV (e.g., xxx:m2)

Loading the database 

dbLoadRecords("$(OPTICS)/opticsApp/Db/ASRPmirrorTable.db","P=xxx:,TBL=MT1:,PITCH=xxx:m1,VERT=xxx:m2")

Or, for the soft motor version:

dbLoadRecords("$(OPTICS)/opticsApp/Db/ASRPmirrorTable_softmotor.db","P=xxx:,TBL=MT1:,PITCH=xxx:m1,VERT=xxx:m2")

After loading the database, set the geometry parameters at runtime or via autosave:

# Distance from pivot to pitch motor (mm)
caput xxx:MT1:pitchArmLen 100.0
# Distance from pivot to fixed point (mm)
caput xxx:MT1:fixedPointZ 50.0

Autosave configuration

Add the following to auto_settings.req:

file ASRPmirrorTable_settings.req P=$(P),TBL=MT1:

This saves and restores the fixedPointZ and pitchArmLen values.

Display files

File Description
ASRPmirrorTable.adl Full display with schematic and coupled pitch control
ASRPmirrorTable_small.adl Compact display with pitch angle setpoint and “More” button