November 2, 2004: Blackberry oatmeal

Patrick attached to SLC Control Program (SCP) from XP laptop on visitor
subnet and shared application via NetMeeting with remote participants:
Bob Dalesio (Baltimore, MD) and Josh Stein (APS, Chicago, IL).

Here is an overview of what we looked at:

1. Config files 
Note that config data for the SCP is in ascii flat files. There are many
separate config files used to run the SCP and there is no way to manage
them via the SCP. Operators have written their own scripts to manage
this task. These scripts can even push buttons on the SCP so that a
routine set of activities can be done from a script. 

Getting a config file active requires two steps: first, it must be loaded.
Then, it must be activated. Loading puts values into BCON fields; activation
puts values into BDES fields.

It's possible to activate a "partial" config. This is where the operator
is able to say to set up only a subset of items; for example, just the 
x-correctors or another particular type of primary.

There is a "Gold config index" which is a protected configuration which has
restricted permissions. Anyone with privileges to change this, must annotate
their changes, too.

2. Looking around LI22 devices
BDES can be manually set via knob utility. Operators like physical knobs
they can turn, so these were created. APS used the Sundial application
for this, but abandoned it. Arrow keys are a variation that operators
seem happy with.

Restor Knob function. Not all commands have knob feature. Consider PTRB
vs. TRIM.

Knob granularity is operator-defined. They can set up the size of a step.

Multi-device knob control - a knob can be defined to control multiple devices.

Most common mistake operators make is mixing up PTRB with TRIM function

There is a GUI-builder to define knobs to control devices

3. Analog Status Index

These are the history plots. We looked at plots of temperature
histories. The time interval to display can be changed. Data is logged
to history file every 6 minutes. After one week, data is sparsified by
dropping 9 out of 10 points (yes, a single spike could be thrown away).

Where "M" is written on the plot, this means that the micro was down (off).

For the display, there are some flags you can set; for eg. "ignore flyers"
would drop outliers from the display.

Besides time series, you can also plot as a histogram.

On to correlation plots... you can select different types of plots: A vs B
shows you a correlation.

There is no way to dump the numerical data to a file but Matlab routines
exist which pull data from the history data.

Here's a limitation to recognize: for the SCP, one user locks out other users
while they are looking at an orbit. And, feedback runs at a lower priority
than this action, so feedback could be made to wait!

4. Looking at emittance measurement on the SCP

This package contains both BPM and wire scanner inputs in order to
do the measurement. In LI02, a emittance measurement uses 5 wire
scanners. You need at least 3. There is a gated ADC which triggers an
array of measurements. Then a Gaussian fit is done to the data. The
resulting coefficients enable the beamsize to be calculated and the sum
of all the beam sizes leads to a value of emittance. "Matching" is done
to compare measured vs. ideal beamsize and the mismatch is quantified 
in the BMAG number. A perfect match has BMAG=1.

For LCLS, emittance is a key parameter. Above a threshold emittance, the
laser won't work!

Note: a wire scanner is in the "marginally invasive" category of beam
diagnostic devices.

5. Timing Index

Looking at the LI02 Trigger Panel, we can see what the triggers are.
An example here is that you could put the wire scanner into the beam and
then adjust the timing until you see what you're looking for.

It's a graphical way to see what's happening on which beam code. For the
SCP, there are 3 pulse advanced beamcodes.

That's all we had time for, even spilling over until 11:30. Patrick notes
that a SCP operator is trained for several months (!) on the capabilities
of the SCP, so it is only the tip of the iceberg what we have looked at
today.