OFF - Places station on OFF state.
There will be no drive power and no klystron high voltage. Beam abort will be active, no beam possible.
PARK - Klystron is OFF but the cavities are sent to their "PARK" frequency.
This frequency is usually +/- 340 kHz from 476 MHz, corresponding to 2.5 revolution harmonics from the RF carrier. The park frequency is entered on the Inp&Consts (input and constants) Tuner panel which can be accessed from the Tuners panel. If all interlocks are made up, the beam abort will clear once the tuners have reached their park positions.
If HVPS or klystron work is required on the station while beam is ON, the station must be both PARKed in order to clear the beam abort AND toggled offline (see description under "General Operational Settings" below) so that all klystron interlocks are ignored by the RF PLC and all HVPS interlocks are ignored by EPICS.
TUNE - Klystron is driven by a constant amount of drive power and no RF feedbacks are possible.
The drive power level is set by the "Saturatd Drive Pwr (W)" entry on the right side of the panel. This mode is intended to be used for RF processing and diagnostics, not for stored beam.
ON_FM - Used to frequency modulate the klystron to help RF process the cavities.
There are two FM files which the system will load into the built-in network analyzer DACs and continuously played through the LLRF system. The "Swept Sine" selector button allows the user to chose the rate of the frequency sweep - either 400 Hz or 1000 Hz. The file names can be reviewed at the lower portion of the System panel. These files are generated by running the Matlab script "make_sweep.m". The drive power level is fixed when the file is generated but can be altered in new files by editing the "ampl" variable before running the script. Typical value for ampl is currently 0.07, 1.0 is full scale. In ON_FM, tuners are set to their "Home" positions.
ON_CW - Normal operating mode.
The gap module generates the baseband RF reference used by the RF Processing module to generate the klystron drive after the RF feedback loops have modulated the signal (if RF feedbacks are on). The ripple loop will operate to keep the phase across the drive path constant (if active).
Auto Reset Tries Left - Number of attempts the station will automatically reset itself and re-energize after a fault. Maximum value is 25. If this entry is non-zero, the station will attempt to reset itself after the fault files have been written (if fault files are enabled on the Fault File Panel). If successful, the station will return to the mode it was in before the fault occurred. For example, if the station was processing in ON_FM mode and faulted, it would return to ON_FM mode if the automated reset sequence was successful. If set to zero, Auto Reset is disabled.
Fast Turnon - When enabled, the station will turn on to a preset HVPS voltage (set on the HVPS panel - "Fast Turn-on Voltage"), a preset number of Gap module DAC counts (set on the Gap Voltage panel - "Faston GAP counts"), and with all the RF feedback loops activated. The station will be ready for beam in ~15 seconds. Without Fast Turnon, the station comes up with direct and comb loops OFF and goes through a tricky sequence of slowly ramping up loop gains (direct then comb), ramping up station gap voltage and finally ramping up the drive power. This sequence takes 1-2 minutes. Fast Turnon should be disabled if a station repetitively trips while trying to Auto Reset.
Max Cav Vacuum (Torr) - Maximum vacuum level tolerated during automated processing. Auto processing (when activated) will slowly increase klystron power until this or one of the other limits are reached. Nominal value = 2e-9 Torr.
Max Cav Gap Voltage (kV) - Maximum gap voltage allowed in any of the station cavities during automated processing. Auto processing (when activated) will slowly increase klystron power until this or one of the other limits are reached. Nominal value = 800 kV.
Max Klys Fwd Pwr (kV) - Maximum klystron output power allowed during automated processing. Auto processing (when activated) will slowly increase klystron power until this or one of the other limits are reached. Nominal value = 460 kW HER, 300 kW LER.
HVPS Loop Mode - Used to determine how EPICS sets the klystron HVPS operating voltage. In OFF mode, the station will come up and stay at either the "Fast Turn-On Voltage" (if Fast Turnon is enabled) or "Stn Turn-On Voltage", where these parameters are set on the HVPS panel. If the loop is switched to OFF during operation, the HVPS voltage will stay at the present level. In PROC (process) mode, the station will use the three above parameters to slowly increase the klystron power to RF process the cavities. Important note: auto processing must be done with direct loop OFF because control points change when loop is closed and the auto processing task is not set up to recognize this. In ON mode, the HVPS output is determined by the Gap Voltage panel under the "Direct Loop OFF" subheading when the direct loop is not enabled, or by the Drive Power panel under the "Direct Loop ON" subheading when the direct loop is enabled. Normally ON.
Stn Online/Offline - When offline, non-RF interlocks related to the klystron are ignored. These include filament, solenoids, water flows and temperatures. All the other interlocks function normally since the beam can induce large cavity voltages and RF powers if they were tuned to a beam harmonic. Offline mode can also be achieved by turning the key on the RF Local panel in the RF racks. Note that to clear the beam abort, the station must be placed in the PARK state.
Stn Gap Volt (kV) - Station gap voltage setting. Station EPICS based control loops will adjust klystron power (direct loop OFF) or Gap module reference output to achieve this setting. See the Gap Voltage panel for more detail.
Stn Phase (Deg) - The phase setting in addition to the "Base" phase (located on the Phase/Pwrs panel) determine the phase of the RF reference from the Gap module. The Matlab script "null_station_phase.m" (accessed from the non-invasive section of the MoreMATLAB panel) will null the station phase and set the proper base phase to preserve the actual RF phase. This script can be run with or without beam since it does not perturb the phase. The script only nulls one station's phase and must be done on every station.
Swept Sine - Selects the sweep rate of the FM modulation used during ON_FM station state. Normally the 1000 Hz modulation is performed first, followed by the 400 Hz and finally by CW processing. The actual file names loaded based on the swept sine selection are located on the System panel.
Beam Tickle - Will play a predetermined modulation through the RF system. Intended to induce a small amount of synchrotron oscillations for diagnostic purposes. Should only be used in ON_CW state. The Tickle file names are located on the System panel. The Matlab script "make_tickle.m" is used to generate the modulation files.
HVPS Voltage Control (kV) - This slider type control/readback is normally just viewed as a monitor of the present HVPS output voltage but is actually a control input as well. With the "HVPS Loop" set to OFF or PROC (process), the user can alter the HVPS setpoint by left clicking the mouse on the slider and dragging the setpoint. Up/Down arrow keys also work after the slider had been selected. A right mouse click allows changing slider control options.
Close - If all necessary HVPS interlocks are made up, this button will close the high power contactor in the HVPS. The present state of the contactor is displayed to the left of the "Close" button.
Drive Pwr Setpoint (W) - Sets the desired drive power for ON_CW state when klystron power is below the "Hi Drive Setting Klys Power (kW)" located on the lower right of the Klystron panel. Nominally 15-25 Watts (klystron tube dependent).
High Pwr Drive Pwr (W) - Sets the desired drive power for ON_CW state when klystron power is above the "Hi Drive Setting Klys Power (kW)" located on the lower right of the Klystron panel. Nominally 20-30 Watts (klystron tube dependent). Designed to operate the tube 10% below saturation at high power levels where HVPS ripple should be small. Produces 90% of full power at full cathode voltage.
Saturatd Drive Pwr (W) - Sets the desired drive power for the TUNE state. Nominally 40-50 Watts (klystron tube dependent). TUNE state is intended for CW processing. Operating the klystron saturated would be the most efficient way (electrically speaking) to CW process the cavities.
See the Drive Power panel for more detail.