The document discusses software development for mechanisms in the Visible Spectro-Polarimeter (ViSP) instrument on the Daniel K. Inouye Solar Telescope. Four unique ViSP mechanisms require control software, including the slit station and grating station. The slit station software controls motion of a slit substation and fold mirror substation to select the desired slit width. The grating station software verifies and rotates diffraction gratings as needed. Significant progress was made in testing motor control via EtherCAT and developing GUIs for slit station and grating station motion control. Further work is needed to finalize the slit station software and develop the focus station software.

1. July 8, 2015
Designing Control Software and Graphical
User Interfaces for ViSP Mechanisms
Alan Sánchez
University of Colorado Boulder - Aerospace Engineering Sciences
High Altitude Observatory - Instrumentation Group

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New instrumental capabilities are needed to meet the challenge of
validating sophisticated models and theories in the field of solar physics
A coronal mass ejection (CME) in a model; the CME is the gray cloud toward the lower right.
Credit: Dusan Odstrcil, George Mason University
This Center for Integrated Space Weather Modeling display is used
to predict space weather.
Credit: NOAA

3. The Daniel K. Inouye Solar Telescope is set for completion in 2019.
It will have broad impacts on astronomy, plasma physics, and solar-
terrestrial relations
http://dkist.nso.edu/node/2220
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http://dkist.nso.edu/node/2764

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http://dkist.nso.edu/node/2739
A total of five science instruments receive light from the First Light
Coudé Beamsplitter, including the Visible Spectro-Polarimeter (ViSP)

5. The ViSP will provide precise measurements of all four Stokes
parameters (I, Q, U, & V) at wavelengths from 380-900 nm
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The wavelength range of optical radiation, with ViSP
capabilities labeled.
Credit: http://light-measurement.com/wavelength-range/

6. All four ViSP-unique mechanisms require robust software to run properly
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7. ViSP mechanisms can be activated either through the
Instrument GUI or the Engineering GUI
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5263-TN-6003
5263-TN-6003. Courtesy of A. Lecinski, P. Oakley, and R. Casini

8. ViSP distributes tasks to several managers that then
delegate tasks to the workers they control.
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5263-TN-6003. Courtesy of A. Lecinski, P. Oakley, and R. Casini

9. ViSP Main Engineering GUI provides monitoring and control
capabilities for every subsystem in the instrument.
5263-TN-6003. Courtesy of A. Lecinski, P. Oakley, and R. Casini
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Slit Station
Very narrow entrance slit to be placed in the ViSP
optical beam; slit is then physically moved laterally
over the image plane in order to capture the
desired field of view.
Grating Station
Used to hold and position the diffraction grating in
the optical path of the ViSP instrument
Optical Design Overview illustrating mechanical
requirements of slit and grating stations
ViSP Critical Science Plan. Courtesy of R. Casini

11. Slit Station Top Level Components
Slit Substation, FM Substation, and Slit Stage
Selector move simultaneously
● Slit Substation moves the same distance as
the desired slit aperture, while the FM
substation moves half this distance
Desired slit aperture is selected and slit selection
stage moves desired slit in front of a mask. This mask
blocks all light from non-active slits, while allowing
light through the active slit to pass.
Slit Selection Stage
Slit and Fold Mirror (FM) Substations
5263-TN-4031. Courtesy of R. Summers, F. Lawson, and G. Card5263-TN-4031. Courtesy of R. Summers, F. Lawson, and G. Card
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12. ViSP Slit Station GUI
● Identifies limit switch status via
EtherCAT I/O connection
○ Notifies user if limit
switch is triggered, stops
all movement
● Delegates movement to
SlitSelect if current slit width is
not desired slit width
● Delegates movement to
SlitTransit and MirrorTransit,
respectively, if current slit and
FM substation positions are not
required slit and FM substation
positions (for desired slit width)
Slit Manager
SlitSelect
SlitTransit
MirrorTransit
❏ Moves desired slit in front of
mask
❏ Moves slit substation to
required position
❏ Moves FM substation to
required position
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13. Slit Station simulated with two motors via Delta Tau PPMAC
and Beckhoff I/O connections on EtherCAT
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14. 5263-TN-202000. Courtesy of R. Summers, F. Lawson, and G. Card
5263-TN-202000. Courtesy of R. Summers, F. Lawson, and G. Card
Essential functions of Grating Station:
Verify current diffraction grating ‘ID’
Position and hold the diffraction grating in the optical path of the ViSP
Grating Station Top Level Components
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15. ViSP Grating Station GUI
● Identifies grating via EtherCAT
I/O connection
○ Notifies user if grating
is not in place, stops all
movement
● Identifies limit switch status
via EtherCAT I/O connection
○ Notifies user if limit
switch is triggered,
stops all movement
● Delegates movement to
GratingRotate if expected
grating is present and current
angle is not desired angle
Grating Manager
GratingRotate
❏ Rotates to desired angle
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16. We completed several fundamental, overarching goals of the HAO Prototyping
Plan, and also made significant progress in specific mechanism software
● Test Setup and Robustness of Copley Amplifiers on
EtherCAT
○ Network has been scheduled and is up and running
○ Controlling 2 Axes on EtherCAT
● Test Setup and Robustness of Beckhoff I/O on EtherCAT
● Test switch communications from Copley to Delta Tau
✓
✓
✓
HAO Prototyping Plan (2014), A. Lecinski and B. Larson
Next steps:
● Finalize Slit Station software
○ step size, number of steps,
intensity mode
● Focus Station software
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17. Acknowledgments
● Partner: Anthony Anglin
● Mentors: Alice Lecinski and Brandon Larson
● Support: Scott Sewell and Val Sloan
● Interns: Jamie Weiss and Isis Peguero
● JES: DKIST software team
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18. July 8, 2015
Thanks!
Questions?