Displays: See Feedback Control from the Feedback subsystem edm screen.
This shows the control (start/stop/enable/disable) and actuators, for all feedbacks (this Feedback Control) page is usually on an overhead.
The Laser Power Set should always be ON (if any feedback is running or is to be started).
Display Instances:
The Start button on the Feedback Control display, which starts a feedback, must always only be pressed on the overhead display instance of the display, since that instance of the display is the one run from the main host for feedbacks. So (after confirmation dialog), it'll start it on the feedbacks host (lcls-srv02). Ie, don't start them on an OPI, though if you do by accident, you can just stop them and restart them on the overhead display.
If some other user or program toggles the status, the btton will come up red on your instance of the display.
Typical Usage of Feedback control display
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The following feedbacks should be ON in normal operation:
- Bunch Charge
- Gun Launch
- one of the Injector Launch feedbacks
- X Cavity Launch
- one of the Longitudinal Feedbacks
- Before starting a feedbacks, check the reference orbit to establish whether the reference orbit is close to measured.
- Check Laser Power Set and Bunch Charge Settings.
You ca set the desired power and camera intensity
Commands on the Feedback Control Panel:
- Start
- starts new instance of Matlab
- Starts with current act. settings
- Saves current actuator settings for future restore.
- Disable: When a feedback is "disabled"
- A feedback in "disabled" stops making calculations.
The loop technically goes through its loop
Advantage of "disabled" as opposed to "off": - remembers last calculated actuator settings
- remembers running average used in integration (in long. feedbacks)
- Matlab does not exit (this is the main advantage).
.. so there is not a huge difference between Off and Disabled.
- Enable
- Starts new measurements at last actuator settings
- continues running average integration
- Stop
- Complete stop, matlab exits.
Injector Launch Feedback display
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Shows all devices and setpoints and current values, plus lower and upper limits.
Setpoints can be changed from the display.
Current Value. For measurement points, the current value is the measured value that the feedback is using, not the actual value from the PV.
Recognizing Errors
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Three categories of error:
1) Errors detected on (soft) IOC.
These are show by red boxes on feedback displays
2) Errors detected by matlab.
These are show in the edm status string with a colored box.
3) Undetected errors., eg feedback oscillation or running away.
HS/DF: If a BPM meas goes red, the feedback will continue to operate, until the actuator limits are exceeded (probably as a result of compromised measurement vector). If an actuator goes bad, the feedback stops??yes, because if the actuator does not respond the feedback will calculate a larger and larger correction until the it exceeds an actuator limit'
Color codes for devices in a feedback "beamline" display:
Grey - not used in this feedback
Green - used and in good shape
Yellow - warning
Purple - the color purple should not be there, if you see it there is an error in the EDM display - write an Artemis please!
Red - error, the device/state is outside it's limits
Error Messages are displayed after the status label. When the string is boxed in RED, the feedback is disabled.
What to do when there are errors:
- If TMIT or Dispersion is too low beam is blocked or off
- if you suspect a BAD BPM, reconfigure the feedback (DF will show how).
- FB00 error (soft IOC error)
Go to Network edm screen, and restart "Feedback Support"
If you leave feedbacks running when IOC is rebooted, all PVs will be reset. Probably a bad idea. - Stop all feedbacks before rebooting the FB00 soft IOC.
If PS for steering magent dies, does steering feedback monitor the magnet?
Graphs
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A graph of feedback measurements, actuators and setpoints, are available on "Graphics" button off feedback specific displays.
Graphs' values are updating continuously but not beam synchronous.
only last 200 points are on graphics displays, the soft IOC save the last 1000 points. These can be accessed by reading the waveform PVs
Plots don't update when feedback is disabled.
Note that longitudinal feedbacks are averaging, so difficult to correlate with other feedbacks.
Reconfigure Feedback
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Changes made to config take effect only when feedback is restarted
Process for reconfiguring a feedback:
1. Stop the feedback
2. Restore Actuators if you wish (see below for how)
3. Try to find cause of problem (see below for what to check)
4. Set up Machine (see below tips with respect to feedback)
5. Set limits and Gains (see below)
6. Calculate matrices (see below)
7. Collect a Reference Orbit (see below)
Once reference orbit is reset, you can restart the feedback.
To restore actuators:
Use the Restore Actuators button on Feedback Control panel - actuators values will be restored from last saved values.
It allows user to compare the "current" with "original" (saved) values. Can cancel restore at this point.
To Find the Cause of Problem:
- Sig. change in magent setting or RF
- Klys dropped or added
- Sig. change in charge
- Laser cathode alignment change
- Mirror status of bunch length monitor. The mirror must be in
- Check BPMs are online
- Sig. change in feedback setpoint.
To set up machine, some things to look out for:
- Laser Cathode alignment
- Charge setting
- Desired orbit
- Desired bunch length (check mirror is IN)
- Ensure Gun launch settles BEFORE Injector Launch is started
- Ensure Injector Launch settles before X Cavity Launch is started.
Set Limits, Measurements and Gains:
- Use feedback configuration application
Start the config application with the Config (???) button on the Feedback Control panel. - The list of actuators and measurement devices, are in the configuration XML files ???filename.
- Enter reasonable limits for each actuator, state, (???)
- Configure->Measurements
XF1 and YF1 = beam sync. acquisition PVs.
Set limits (set Upper, Set Lower) or hit Get Limits from Device.
If Dispersion is not relevant to the feedback, ignore that box, it's not used.
Ignore "Use Reference Orit for Measurement Error". not used. - Configure->Actuators
From here can choose actuators to be used. - Configure>States and Gains
Keep gains at <0.5.
Only longitudinal uses integral (if you ask for it) - Configure->Matrices
This lets you see matrices in use.
Button Calc New F Matrix calculates a new matrix from the model (we sometimes change the values, so can be useful to recalculate).
Note that gains apply to corresponding function matrix elements.
If someone changes the SLC Model, you will want to use Calc New F Matrix button. - Configure->Timer Parameters
Used for timer in matlab that does the main loop. Don't change these. - Configure->Other feedback parameters.
Changes name of feedback; lets you see config file name etc.
- SAVE the configuration: either File->Exit or File->Save Configuration file. Then RESTART the feedbacks you reconfigured. If you use File->Exit the old file will be lost. If you want to save the current version, then use File->"Save Configuration".
Calculate new Matrix
- Reasons:
SLC Model has changed
Joe, Juhao, DF has changed the device/states. Also reboot IOC
(...)
Collect a new reference orbit
- Use the configuration application for reference orbits. See Reference Orbits menu. Launch the Config app from the Feedback Control panel.
Archive of Feedback Status
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Start/Stop and Enable/Disable, are archived as a PVs.
Suggestions
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- Run matlab as an execed process (so don't need a window). There may be some issue with Joe's watcher.
- Add where states are calculated to Injector Launch feedback display
- Can we have display which is "popped" from dock, always pop to top. Diane was demoing on Windows, presumably the request is for Linux in CR and Windows too. NOTE: If you can't see Close/Resize toolbar, on Windows, you can go to X-Windows dock, select the
- Add capability for user to indicate which measurements (and/or actuators???) are sufficient to run the feedback.
- HS requires to be able to change the error messages.
- Zoe: Put a note on Network panel for Feedbacks Support to say "Stop all feedbacks before rebooting".
- PE: Compare BDEs to BACT to monitor relevant actuator status.
- Put saved actuator values in Save/Restore
- Matlab file dialog is broken - if you try the file save or file load command several times eventually it will work...
- Label system matrix elements to the Configure->Matrices.. Display.