Running LTX

Operator Tasks

• Main operator
• NBI operator
• Spectroscopists

Setting Up

Preparing LTX-β for operation requires following the LTX-β general operations procedure.

Key Equipment

• TF disconnect
• Hoffman Boxes
• TF cooling water
• L-Wing DI water flow controller
• L-Wing DI water valves
• Pumping and Purging
• Vessel filament variac and bias
• Cooling air for beam and coils
• Robicon cooling water
• Robicon front panels
• Robicon breakers
• OH disconnect switch
• OH discharge control software
• OH charging control panel
• Vessel filament bias control software
• Gas fueling valve driver
• Yellow coil bank control panel
• Robicon control software

Taking a Shot

Interface Software

• Bender
  • Run VI: Controls shot cycle, creates MDSplus shot tree, configures and initiates master clock using CAMAC Jorways, reads data from Joerger digitizers

1. cd /home/ltxuser
2. sh ./launchlocalvi.sh
3. (Ignore recovery, click "Cancel") -> Open ClockCycleControl.vi -> Run VI
4. LTXControl.vi is launched-> Click green "Current" button to switch to next shot-> In "Shot Details", enter Operator & Description for next shot
5. Return to ClockCycleControl.vi -> "Start Cycle"
6. Enter Comment after shot and click "Save" to write comment to the tree then return to step 4.

• MATLAB GUI: Programs Chronos analog and digital outputs to control field coil and gas puff waveforms, readies Chronos, writes to the tree.

• Nibbler
  • OH interface VI: Modulation Timer, Fast Digs Scopes
  • NBI GUI (via remote to Fry): Controls NBI
• Hermes
  • RTD interface VI:
  • Thermocouple interface VI:

Backend Software

• Bender
• Leela

Events

• LTX_SOC: "Start of cycle," defined by the creation of a new shot by the run VI, typically at t0-30s.
• LTX_SOS: "Start of shot," typically at t0-25s.
• LTX_PREP: An operator-set advance warning event for scripts that need a few seconds to prepare. Typically set to t0-15s.
• LTX_TM60: A deprecated ancestor to the more intuitively and generally named LTX_PREP. Sent at the same time as LTX_PREP to preserve legacy script functionality.
• LTX_T0: Reference point for other events. Sent (nominally) at t=0 on the main timebase, although variable network latency makes it unreliable as a trigger.
• LTX_EOP: "End of pulse," sent at t0+1s, when the digitizers finish recording and all coils should be (mostly) de-energized.
• LTX_EOC: "End of cycle," when the digitizers are all expected to have finished storing their data to the tree. Typically set to t+45s.
• LTX_AUTO: "Automation," when the automated scripts run on bender have all been run (typically about 30 seconds after LTX_EOC).
• LTX_RECON: "Reconstruction," when the automated reconstruction has completed (typically 3-4 minutes after LTX_AUTO).

Troubleshooting

Digitizers

Dt-Acqs Fail to Store

Occasionally, one or more of the Dt-Acqs will enter a state where it fails to save data to the MDSplus tree. This is most often caused by a reboot of Lithos, which requires step #1 below to be performed for all three Dt-Acqs. The first tier of solutions are:

1. Mode Reset: Run ssh root@<DEVICE> /ffs/rumode (where <DEVICE> is the name of the Dt-Acq) from Bender for each Dt-Acq failing to store. On the first shot following a mode reset, all Dt-Acqs which have been reset can be expected not to trigger properly, so at least a second crates-only shot will generally be necessary.
2. Power Cycle: Switch off all malfunctioning Dt-Acqs. Wait at least 1 full minute before switching them on again. Repeat step #1 above.

Power supplies

Breakers

Related Pages

Neutral Beam - Details on operating the neutral beam system
Analysis codes - A list of data analysis scripts with a brief description of their function and purpose, including those used for post-shot automation.