Page History

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1. In XAL knobs, only a single linear coefficient factor is available as the "knob" value factor; ie no power series or sine/cosine factors.
2. SLC mkbs always "perturb" magnets and klystrons. In XAK knobs, no special action is taken at the level of the GUI, the method is dictated by whatever the PV implements.

Save and Load

• You can save and reload knobs using the File->Save and File->Open or File->Open Recent.

• Note that a .knobs file can contain more than one knob! It contains all the "Groups" and "knobs" that were in the application when you saved.

• So, there are a couple of ways to organize knobs, knobs files, and groups in the knobs files.

• The knobs files are in:

  Code Block
  $PHYSICS_DATA/data/Knobs

Problems and Issues

1. Knobs app can't set non-EPICS devices (eg correctors), so;
   1. In "drilldown" mode it offers you devices to set that it can't in fact set (eg having selected BX02 TO QM15, you select Y corrector YC21303 (which is in fact an SLC CS corrector), select FieldSet (which you shouldn't have been able to do) and then it can't connect.
      WORK AROUND: Be conscious of what's SLC and what EPICS. See resources 0,1.
   2. It makes bumps using correctors it can't set!
      Eg: Select sequence indexes 2,3,4,5. Make Vertical design offset knobs. The first knob created is BPM21301. This contains 3 correctors, all SLC! Eg YXC21303 - YCOR:LI21:303. So, knob can't be implemented. This problem seems particularly acute for Vertical bumps! Are more of our horizontal correctors EPICS?
      NO work around. *Will have to fix so that that elements which are not settable="true" in the xdxf file, are not included.
2. Knobs->"Proprotional Coefficients" spelt wrongly.
3. Knobs Editor uses SNS type names, which themselves use >1 name eg hcorr == dch == horrzcorr => X correctors.

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