1. BLU-ICE & The Distributed Control System Past, Present, and Future
Scott McPhillips Stanford Synchrotron Radiation Laboratory

2. Overview Review the core features Example Applications
DCS 1.0: Centralized Message Routing Architecture
DCS 2.0: Scripted Devices
DCS 3.0: Scripted Operations
Example Applications
Automatic Loop Alignment
Data Collection
Crystal Screening
Plans for releasing DCS 3.0

3. What is a core feature?
Features that could persist in a completely different environment.
Features that simplify hardware control & integration.

4. DCS 1.0: Software Components & Acronyms
XOS (Cross Operating System library)
Provides subset of system calls with O.S. independent API.
BLU-ICE (the GUI interface)
Multiple, fully synchronized clients
Written in TCL.
Simple scripting available.
Scans
Hardware testing
DHS (Distributed Hardware Servers)
Translates DCS protocol into hardware specific protocol.
DCSS (The Distributed Control System Server)
Centralized process
1 DCSS per beam line.

5. DCS 1.0: Basic Architecture
BLU-ICE(s)
DCSS is the central message router
BLU-ICE clients connect to DCSS only.
Hardware servers connect to DCSS only.
DCSS records the state of the beam line.
Benefits
Fewer interfaces / less complexity.
Easier system level debugging?
Persistent & current state available in 1 place.
DCSS
Hardware Servers
Beam Line Hardware

6. DCS 1.0: Limitations
BLU-ICE(s)
Combo motors not support natively in DCS 1.0.
Requires lower level control system to support these features.
DCSS
table_vert
table_vert_1
table_vert_2
Table
table_pitch
table_pivot
ICS Wrapper DHS
Galil DHS
ICS control system
Beam Line Hardware

7. DCS 2.0: Scripted Devices DCSS TCL Scripting added to DCSS. Core
DCSS sits above all of the hardware servers.
Relationships can be defined between devices spanning multiple hardware servers.
BLU-ICE
DCSS
TCL
Scripting Engine
Core
Scripting engine obeys and depends upon centralized messaging.
Connects as “GUI client.”
Connects as a DHS.
Hardware Servers
Beam Line Hardware

8. DCS 2.0: Scripted Devices
Support for unlimited parent and “grandparent” hierarchy.
beam_size_y
slit_1_vert_gap
slit_2_vert_gap
slit_1_upper
slit_1_lower
slit_2_upper
slit_2_lower
Virtual motor support (e.g. table_pivot)
table_vert
table_vert_1
table_vert_2
Table
table_pitch
table_pivot

9. DCS 3.0: Operations
Added a generic “Operation” message to the DCS protocol.
Allows easy integration of new types of hardware.
DCSS routes the operation request to the responsible DHS.
Added “scripted operation” capabilities to the scripting engine.
Scripted operations can
do anything possible in TCL.
move motors or scripted devices.
wait for motors to complete moving.
Start other operations (DHS or scripted).
wait for operations to complete.
Scripted devices can start operations.
DCS protocol messages are unlimited in size.
Removed the 200 byte message size limitation.
DCSS is backward compatible with old hardware servers.

10. DCS 3.0: Example Application #1 Automatic Loop Alignment
BLU-ICE
Wrote “camera” DHS with operations for retrieving and processing images.
“getLoopTip” will return image coordinates of tip of sample.
“addImageToList” takes a picture and stores it in memory.
“findBoundingBox” looks at images in memory and finds 3D bounding box for loop.
Wrote Scripted Operation “centerLoop.”
Calls the “camera” DHS operations.
Moves motors.
Script handles the high level centering decisions.
Center loop
DCSS
centerLoop
Image
operations
Move motors
Camera DHS
Motor DHS
Axis Server
Motion controller
Sample camera

11. DCS 3.0: Example Application #2: Data Collection
collectRun
collectFrame
gonio_phi
detector_z_corr
optimizedEnergy
Legend
collectRun operation does the following:
Moves motors to the next frame’s position.
Waits for the motors.
Starts the operation “collectFrame”.
Waits for the collectFrame operation to complete.
Loops over the above steps until the run is finished.
Scripted Device
Scripted Operation
“Real” hardware

12. DCS 3.0: Example Application #2: Data Collection
collectRun
collectFrame
gonio_phi
detector_z_corr
detector_encoder
detector_z
optimizedEnergy
optimize
Legend
energy
Scripted Device
table_vert
Scripted Operation
ion_chambers
“Real” hardware

13. DCS 3.0: Example Application #2: Data Collection
collectRun
collectFrame
gonio_phi
detector_z_corr
detector_encoder
detector_z
optimizedEnergy
optimize
Legend
energy
Scripted Device
table_vert
table_slide
Scripted Operation
ion_chambers
mono_angle
“Real” hardware
table_horz_2
table_horz_1
table_vert_1
table_vert_2

14. DCS 3.0: Example Application #2: Data Collection
collectRun
collectFrame
gonio_phi
expose
detector_z_corr
detector
gonio_phi
detector_encoder
detector_z
optimizedEnergy
optimize
Legend
energy
Scripted Device
table_vert
table_slide
Scripted Operation
ion_chambers
mono_angle
“Real” hardware
table_horz_2
table_horz_1
table_vert_1
table_vert_2

15. DCS 3.0: Example Application #3: Crystal Screening
centerLoop
optimizedEnergy
Video Snapshot
collectFrame
Mount Next Crystal
Legend
Beamstop_z
Scripted Device
Sample_x,y,z
Scripted Operation
Gonio_phi
detector_z
robot
“Real” hardware

16. DCS 3.0+: Development Environment
All code stored in CVS (Concurrent Version System)
External collaborators can see what is being worked on at SSRL.
Absorb architecturally consistent changes from external collaborators.
Open the software portions of Bugzilla to external Collaborators?
Engineering change requests already being tracked at SSRL.
Create an online discussion group?
Allow collaborators to discuss design changes, problems, and solutions without opening a bug report.
Documentation
DCS Administrator’s Manual
Script Writer’s Guide

17. Acknowledgements Developers Scientific Input Team Leaders
Tim McPhillips, Guenter Wolf, Henry van den Bedem, Ken Sharp, Nick Sauter, Jian Zhong, Hilary Yu, Thomas Eriksson
Scientific Input
Paul Ellis, Aina Cohen, Ana Gonzalez, Mitch Miller, Irimpan Mathews, Dan Harrington, Ezequiel Panepucci, John Coller, Hsiu-Ju Chiu, Ashley Deacon, Paul Phizackerley, Jeanette Hobbs, Linda Brinen
Team Leaders
Peter Kuhn, Mike Soltis