1. Operations Machine Simulator.
Adrian Johnson
Senior Operations Technician
Diamond Light Source 1

2. Overview of Diamond 3rd Generation Light Source.
Opened for Users in 2007.
Currently 26 operational Beamlines.
4 Beamlines currently under construction.
Total of 32 Beamlines by 2017. 2

3. Overview of Diamond Accelerators
100MeV Linac
3GeV Booster
3GeV Storage Ring
561.6m Circumference.
300mA stored beam.
Running in Top up (10min cycles). 3

4. Why create a simulator?
The actual machine is rarely available for Training purposes.
When providing beam for Users aiming for Stability and reliability.
Machine development time is in high demand.
So a simulator would be useful for:
Training New Operators.
Refreshing Existing Operators knowledge.
Demonstration purposes.
Work Experience students.
Tours / Visits. 4

5. Aims of the Operations Simulator
Software simulation of accelerator operation.
Not an Accelerator Physics Model.
Real time emulation of the machine sub systems.
Look, feel and behave realistic.
User interfaces that mimic the real machine
But not look too realistic – avoid confusion.
Relatively simple to create and maintain.
Empirical data taken from the machine used to create behavior.
Modular build to make it easy to add more complexity / realism. 5

6. Simulator Architecture
Process Variable (PV) Store.
To store: States, Set points, Waveforms etc.
Process Script.
Reads States, Set points etc.
Mimics machine behavior,
Writes new States, etc.
User Interfaces.
Controls, On/Off, Start/Stop, Set points etc.
Displays of States, Plots, Set points, etc. 6

7. Simulator Architecture
Process Variable (PV) Store.
Originally tried a PostGreSQL Database to hold ‘fake pv’s’.
Communication via Python was too slow, abandoned.
EPICS Soft IOC with Real PVs
IOC : Input / Output Controller
Runs in a terminal on a PC in the Control Room.
No hardware connected.
Currently about 200 PVs in Simulator.
Only acts as a PV store, doesn’t contribute to behavior. 7

8. Simulator Architecture
Process Scripts.
Written in Python.
Small simple scripts to mimic the behavior of parts of the machine.
Easy to update, easy to add more complexity and realism.
Run independently in terminals on same PC as the IOC.
Processes Written So Far.
GUN,
Gun RF, Gun Charge.
LINAC,
Linac RF, Linac Charge and Linac to Booster Efficiency, .
BOOSTER
Booster RF, BR Charge / Current, Booster to Storage Ring Efficiency.
STORAGE RING RF,
Cavity Volts and Phase, Forward Power.
BEAM,
Beam Injection, Beam Lifetime, Fill Pattern, Power Demand.
STORAGE RING MPS,
Interlocks for Temperatures, Flows, Vacuum, Beam Position. 8

9. Simulator Architecture
Gun Process as an example. 9

10. Gun Process Behaviour GUN Bias adjustments vs GUN Charge.
Multi-Bunch
Single-Bunch
Striptool plots of Simulator pvs 10

11. Simulator Architecture
Simulation Schematic. 11

12. Effect of Linac Volts on Charge and Currents
Behaviour Examples
Effect of Linac Volts on Charge and Currents
Lifetime vs Cavity Volts
Striptool plots of Simulator pvs 12

13. Simulator User Interfaces
Behave like real machine with multiple operators.
Mostly Written in Python,
EDM being phased out at Diamond,
Made Obvious which is Simulator and which is Real.
Tried to retain some realism.
Real Machine GUI
Simulator GUI 13

14. Simulator User Interface examples
Real GUI
Simulator GUI 14

15. Trip Simulator Trip Editor to create / edit trips. Trip Simulator
Defines the states for a single or set of PVs to initiate a trip.
Creates a saved set.
Trip Simulator
Select a pre-defined trip,
Select a Random trip. 15

16. Trip Simulator
Effect of Cell12 Gauge Controller trip. 16

17. Where Next Power Supplies Beam Properties Top up. PSS Vacuum.
Most are On / Off effects.
Transfer line Steering impacts Injection
Pulsed magnets (amplitude and timing) impact Injection.
Beam Properties
Orbit,
Tunes,
Coupling,
Top up.
PSS
Mostly On / Off effects.
Radiation monitors.
Vacuum.
Insertion Devices.
Front Ends. 17

18. Summary
Turned out to be surprisingly simple to create an Operations machine simulator.
It works well, feels and behaves realistic.
Worth doing,
So far only used by Work experience students.
It’s now available to any new Operators for training.
Expanding all the time.
Long term project to keep it growing and up to date. 18