Lab

1
Lab 1CA Clients

2
Lab 1EPICS CA Clients

• Real Life Example 1 After assembling the ioc
  and configuring the EPICS database, the
  application developer left on vacation right
  before your scheduled commissioning shift. Using
  a variety of tools (Channel Access Clients), you
  will interact with the new LINAC and try to
  achieve your commissioning milestones.
• Your goals for the shift are to
• Transport beam to the end of the LINAC
• Optimize beam transport
• Measure the beam energy using a bending magnet
  and faraday cup
• Stabilize beam current with simple closed-loop
  control
• Full documentation on the Knob Manger, BURT, and
  ALH can be found at http//csg.lbl.gov/EPICS/Re
  commendedDocs.html

3
Virtual LINACTheory of Operation

• Beam is generated from the electron gun when the
  cathode temperature (studnt_cathodeTempM) is gt
  130 degrees and the gun is enabled
  (studnt_gunOnC 1). The cathode is heated by
  adjusting its current (studnt_cathodeCurrentC)
• Beam is steered down the linac using 5 sets of
  correctors. Each set consists of a horizontal
  corrector (studnt_HnsetCurrentC) and a vertical
  corrector (studnt_VnsetCurrentC) n1-5
• The gate valve must be opened to get beam past
  PM2 (studnt_GV1positionC 1)
• Diagnostics
• one current monitor (studnt_CM1intensityM),
• five BPMs (studnt_PMnXpositionM,
  studnt_PMnYpositionM, studnt_PMnintensityM)
• two faraday cups (studnt_FCnintensityM)

4
Tasks

• Complete an medm display to interact with the
  virtual linac
• Write a shell script to calculate a useful
  parameter (transport efficiency)
• Use the Knob Manager to provide convenient
  control of power supplies to maximize transport
• Configure a StripTool to trend important
  parameters
• Use burtrb/burtwb to save/restore settings
• Configure the Alarm Handler to monitor critical
  parameters
• Use some APS OAG tools to find optimum settings
  and implement closed loop control
• Write a script to automate linac startup/shutdown
• Experiment with other clients (cau, wingz, etc)
• HINT If you need assistance, studnt0 has
  already completed the lab exercises

5
MEDM

• Develop an medm display that allows interactive
  control of the power supplies, electron gun, and
  gate valve (begin with /host/medm/linac.adl)
• Suggestions
• Add sliders for control of corrector power
  supplies
• Add text entries for control of cathode heater
  and bending magnet supply
• Add Choice Buttons for studnt_gunOnC and
  studnt_GV1positionC
• Transport beam down your linac
• Increase the cathode current until Cathode
  Temperature exceeds 120 degrees.
• Turn on beam using studnt_gunOnC
• Steer beam down linac using corrector supplies
• Open Gate Valve
• Optimize steering to end of linac

6
MEDM(cont.)

• More features
• Make a warning message appear on the display
  whenever the Beam On button is depressed
  (studnt_gunOnC ! 0). Use a text widget with
  Visibility set appropriately.
• Create a new display that has a strip chart to
  trend the cathode temperature. Place a related
  display menu on the main display to call up the
  strip chart display. Try using the invisible
  attribute to make a hot button on the image of
  the gun that brings up the strip chart display.

7
Unix shell commands

• Experiment with the shell tools provided in the
  EPICS distribution (type the command without any
  arguments for a usage line)
• caget
• caput
• cavget
• cavput
• caGet
• caPut
• cawait
• caInfo
• Write a simple shell script (csh, perl, etc.) to
  calculate transport efficiency (FC1/CM1). Write
  this calculated value (caput) to a spare PV in
  the ioc (studnt_opVariable1). Add a text monitor
  on your medm screen to display this value.
• Help files for c-shell and perl are located in
  /host/scripts.

8
Knob Manager(km)

• Start the knob manager client (km )
• Drag and drop PV names of corrector supplies into
  knob manager knobs
• Use knobs to optimize steering down the LINAC
• Investigate Knob Manager capabilities
• Knob Disable
• Memory
• Up/Down Arrows
• Save the knob manager configuration in the
  /host/km directory
• Add a shell command menu to the medm display to
  call up a pre-configured knob manager
• e.g. km -filename ltconfigFilegt

9
StripTool

• Start the StripTool (StripTool ) and create a
  configuration that trends the cathode
  temperature, cathode current, FC1 current, and
  transport efficiency (updated by previous shell
  script)
• Attempt to achieve maximum transport efficiency
  of beam by steering while monitoring the strip
  chart.
• Save the StripTool configuration in
  /host/stripTool/
• Add a shell command menu on the medm display to
  call start a pre-configured StripTool.
• StripTool ltconfig_filegt
• Investigate other features of StripTool
• Drag other PVs directly to plotting area
• Zoom In/Out
• Right mouse button on plotting area menu

10
Backup/Restore(burt)

• burtrb saves the value of a list of PVs that
  are listed in a request file (filename1.req) to
  a snapshot file (filename2.snap).
• Type burtrb for a usage line
• Save settings burtrb -f linac.req -o
  settings1.snap
• Request file syntax
• One PV name per line
• If PV is preceded with RO (Read Only), the PV is
  stored in the snapshot file by burtrb but not
  restored by burtwb.
• Examine linac.req and settings1.snap
• burtwb restores the value of PVs as saved in
  the snapshot file
• Type burtwb for a usage line
• Restore settings burtwb -f settings1.snap
• Add a shell command menu on the medm display to
  save and restore power supply settings from the
  medm display. Provide two commands that store in
  different files and two restore commands.

11
Alarm Handler (alh)

• Start the alarm handler (alh ) and open the
  configuration file /host/alh/linac.alhConfig.
• Create alarm situations and interact with the
  alarm handler
• Investigate other alh capabilities
• Add alias names for the PVs (ALIAS)
• Add the capability to bring up the strip chart
  medm display from the alarm handler when the
  Cathode Temperature PV alarms (COMMAND)
• Add simple HELP text for the operator for the
  Gate Valve PV (GUIDANCE )
• Configure the alarm handler to ignore the cathode
  temperature alarm if studnt_gunBakeoutC 1
  (FORCEPV)
• Add a GUIDANCE command for the top group to
  bring up your favorite web page
• Add a shell command menu on the medm display to
  call up this pre-configured alh (e.g. alh/
  linac.alhConfig).

12
Miscellaneous OAG Tools

• Use quickExperiment to find the optimum BM1
  current to bend the beam to FC2
• Obtain as much beam current as possible at FC1
• cd to /host/sdds. Start quickExperiment (a
  TCL/TK application) and configure
• Measurement PV - studnt_FC2intensityM (use
  NAME CAPTURE to drag/drop)
• Variables PV - studnt_BM1setCurrentC
• Steps 50 Initial 200 Final 225
• Output File - ./bm1Scan
• Press Run. Wait for it to complete the ramping
  cycle
• Press Plot ./bm1Scan
• Select Mouse Tracker from the Options menu and
  determine optimum current for bending magnet.
• For more info on quickExperiment , use the
  context sensitive Help

13
Miscellaneous OAG Tools

• Use maintainReadback to stabilize cathode beam
  current (observe result using the StripTool).
• Obtain as much beam current as possible at FC1
• Start the StripTool to trend cathode temperature
  and FC1 current (use the previously developed
  configuration file). Note the oscillation in
  cathode temeperature.
• cd to /host/sdds. Start maintainReadback (a
  TCL/TK application) and configure
• Readback studnt_cathodeTempM
• Actuator studnt_cathodeCurrentC
• Hold 157 Change limit 1 Gain .2
  Action limit 0 Pause 1 Steps 100
  Samples 1 Mode Integral
• Press Run
• Monitor the strip chart to see effect
• For more info on maintainReadback, use the
  context sensitive Help

14
Automate Routine Sequences

• Write a LINAC ON shell script to perform the
  following
• Launch medm with the appropriate display
• Heat up gun cathode to optimum temperature
  (studnt_cathodeTempM.SEVR 0)
• Restore optimum settings for best transport (use
  burwb and a previously saved snapshot file)
• Launch alarm handler to monitor LINAC
• Turn on the gun
• Open gate valve
• Write a LINAC Off shell script to perform the
  following
• Turn off gun, lower cathode heater current
• Close gate valve
• Turn off all power supplies (set current to 0)

15
Additional Clients

• Probe
• Start probe probe
• Drag/drop a PV from the medm display
• Investigate probe features
• wingz - Spreadsheet
• cd to /hosts/wingz
• Start wingz wingz caWingz.wkz
• Replace (user) with studnt_
• Select a cell to the right of a PV name. Hit
  caGet to retrieve, caPut to send
• Select multiple cells to perform backup and
  restore functions
• cau - Channel Access Utility
• Start cau cau
• type ? for a list of commands
• monitor several PVs from the LINAC