Auto Chromaticity Measurement Program

There is a new program that is meant to help set the tunes chromaticities, and coupling for Tevatron Shot setup.  The program is currently installed on page T52 and the image is shown below.

Program function:

There are a list of functions on the left side of the page.  These functions are meant to be sequenced through when the program is called by the sequencer, but they can be executed one by one when the the program is running in stand alone mode.   This program uses the tune and chromaticity trackers built by CY Tan.  In the upper right portion of the page, there are a set of Fast Time Plots that are used to monitor the programs operation.  In the lower right portion of the screen, there are a list of utility functions used in measuring the tunes and chromaticities.

Sequenced Operation:

The sequencer starts the program on a remote console (CLX105  for now), and it begins running immediately.  The fast time plots start at the appropriate times.  There is a status window in the middle of the page that is meant to keep the user informed about the progress of the program.  More detailed messages scroll by in the message window.  Status is reported to the sequencer message window so the operator can be aware of progress without watching the remote console.  If things run without error, the sequencer should wait until all the tunes, chromaticity, and coupling are set and then move on.  Aborting out of the sequencer wait will necessitate doing the entire tune up from the beginning.

The first operation is to split the tunes for the chromaticity measurement to .572 and .590.  The chromaticity trackers are then turned on and the Injection chromaticity mults are adjusted in order to bring the un-corrected chromaticities to near 4 units in each plane. 

At that point, the chromaticity trackers are turned off, and the tune trackers are used for a verification measurement.  The tunes are plotted as the RF frequency is ramped through +/- 40 Hz.  The measured tunes at the maximum RF excursions are used to calculate the chromaticity. 

At this point, page C43 is started on the sequencer console.  For now, operators should use page C43 as they always have to set the chromaticities between 3 and 4 units in each plane.  When page C43 starts, the tunes should already be in the proper place (.572 and .59) with the tickler on.  Measure the chromaticities and adjust as necessary.  When the chromaticities are acceptable, answer OK to all of the decide boxes including the one that asks if you are ready to move on to the coupling measurement.

At this point, the tune trackers will again be used to set the tunes to a proper place to use page C101 for a coupling measurement.  Then C101 will be called up on the sequencer console, and the operator will be asked to set the coupling using that page.  Once the coupling settings are done and verified, click on the OK button on the decide boxes including the one asking if you are ready to have the tunes set for HEP injection.. 

The tune tracker will once again be turned on and the tunes moved to the proper place for HEP Proton injection.  Copies of the fast time plots will automatically be put in the Tev E-log if the sequence finishes successfully.  Verify that the tunes are OK for injection and continue with Proton loading.

State Devices Used:

This process uses a couple state devices to let page T52 communicate with pages C43 and C101.  Before page C43 is called up, page T52 sets the device V:C43SEQ to a value indicating that a sequencer request is present.  Page C43 uses this value to know that it should ask the operator if they are ready to move on when the chromaticities are set.  If the operator answers OK, the state device is set to a value indicating that the program run is complete.  The same technique is used for communication between T52 and C101 using the state device V:C101SQ.

Program Failure:

If the program experiences an error that it does not know how to handle, tune and chromaticity knobs are restored to their values at the beginning of the programs operation.  The program can be run again from this point, or some of the operations may need to be done by hand.  Failures include not being able to set the tunes and chromaticities to the desired values in a reasonable number of iterations.  Hopefully failures will be rare (we will see).