CRYRING Injection Bumper

Hardware Description

Purpose

Injection bumpers are used for multiturn injection: Before beam injection, in the injection area the closed orbit is shifted. During injection the orbit distortion is reduced while beam is injected continuously. This slow reduction of the injection bump during the injection process provides for winding beam contnuously for several turns.

The CRYRING uses electrostatic bumpers. By HW trigger (trigger by a FESA real-time action would be not accurate enough) a voltage is switched on which is then decreased continiously to zero. To adjust to the beam parameters, the starting voltage as well as the duration of the bump fall time can be varied.

Outline

All four bumpers in the ring are supplied the same common power supply.

Two power supplies are available, one for high voltages (30 kV) and short decay times, and one for a lower voltage range (1 kV), with longer decay times. Using maually operated plugs, the bumpers (all four commonly) can be connected to either one of the two power supplies. Two seperate plugs, one for positive and one for negative voltage output, must be set.

Interface to the Equipment

Power Supplies

Both power supplies provide a nearly identical control system interface. The bumper power supplies require three setting parameters:

• output voltage (analogue voltage)
• adjustable fall time values (analogue voltage), seperate settings are foreseen for positive and for negative output
  • fall time for posiive output voltage
  • fall time for negative output voltage

The 30 kV bumper power supply provides additional digital control:

• it provides status Information, like
  • power on / off
  • remote / local
• it provides control Input, at least
  • power on / off

The 1 kV bumper power supply provides no digital control.

No acquisition values are provided.

Time Control

Both power supplies require a HW trigger pulse to generate the voltage bump. On each power supply the trigger signal has to be provided to a BNC connector input.

Power Supply Selector Switch

The power supply selector provides read-back of the positions of the power supply selector, presenting four bit of information:

• positive voltage plug properly inserted
• negative voltage plug properly inserted
• position of positive voltage plug, set to 1 kV or to 30 kV power supply
• position of negative voltage plug, set to 1 kV or to 30 kV power supply

Documentation

More information on the Hardware is presented in the HW-Wiki on page Electrostatic Bumper.

A rough description, provided by Mats Engström, 20. May 2013, is attached as Bump.pdf. Additional information is provided in the HW-Wiki on the page Electrostatic Bumper.

Equipment Modeling

Control System Devices

All four bumpers in the ring are supplied by the same power supply. Therefore in the control system only one single device, represented by one single nomenclature, will be installed.

Parallel Operation of Both Power Supplies

Similar to the former operation of the CRYRING in the Manne Siegbahn Institut, both power supplies will be combined into one device, the bumper supply. This means:

• the device 'Bumper' has only one set of setting values, used for both physical power supplies
  • one value 'voltage': voltage of output pulse
  • one value 'fall time': decay time (duration of decrease) of output pulse, value will be used for both positive and negative pulse
• the front-end sofware evaluates the position of the power supply selector plugs:
  • the position of the selector plugs is provided as acquisition
  • the range of the voltage value, provided by the 'voltage_max' max-value-item, is set according to the selected power supply
• the front-end software checks whether the setting data fit to the selected power supply:
  • Two checks are implemented,
    • a check in the property, data-setting is refused in case of mismatch,
    • a check in the real-time Action. In case of mismatch:
      • pulse generation is suppressed by providing 0 Volt to the power supply (trigger generation will not be affected)
      • an error-flag in the acquisition property is set
• In addition to values for voltage and fall time, a value for the required setting of the power supply selector plugs is requestet. The setting-property provides therefor three value-items (voltage, fall time, selector plugs position). The additional value for the selector plugs position indicates, whether setting data are generated for the low voltage or the high voltage power supply. These data will not change the selector plug positions, the are only used to check whether the selector positions are in the position which is requested during data generation.
• inconsistent setting of selection plugs (one set to 30 kV, other set to 1 kV) has to be handled as internal error state:
  • operation of bumper has to be disabled (no trigger pulse) by providing 0 Volt to both power supplies
  • error-indication in device-Status and set opReady-flag to false
• the control system interface will always be connected to both HW power supplies, using different sets of DACs for both power supplies. Corresponding to position of power supply selection plugs:
  • provide DAC-outputs only for selected power supply,
  • provide set voltage of 0 Volt for non-selected power supply

Property Layout

Proposition for Properties - not strict specification.

property name	prop. type	value-item	type	unit	meaning	impl
Status	status	status	DEVICE_STATUS	-	UNKNOWN/OK/WARNING/ERROR
		detailed_status	DETAILED_STATUS	-	See extra table (to be added)
Power	power	power	DEVICE_MODE_POWER (enum -> int)		ON=1 / OFF = 2. Works only for High-Voltage power supply.
Reset	reset
Init	init
Version	version
Setting	setting	voltage	double	volt	peak voltage reference value, range 0 - 30 kV or 0 - 1 kV, depending on selector switch
		fallTime	double	-	Bump fall time (duration of trailing edge. No unit, since nonlinear dependency between value and time. Range 0.0 (longest) to 1.0 (shorlest)
		powerSupply	enum	-	0: not set (read only), 1: low power, 2: high power
Acquisition	!?!? bumper does not provide acquisition data, except of power supply selector switch ?!?!
	acquisition	voltageSet	double	volt	Amplitude reference value
		fallTimeSet	double	-	Bump fall time set, 0.0 (shortest) to 10.0 (longest). Used for both positive and negative Outputs.
		powerSupplySet	enum	-	desired position of power supply selector plugs 0: not set, 1: low power, 2: high
		powerSupply	enum	-	actual position of power supply selector plugs 0: not set 1: low power, 2: high, 3: inconsistent; also see remark 1
PowerSupplySelector	acquisition	powerSupply	enum	-	0: not set, 1: low power, 2: high power, 3: inconsistent. Position of power supply selector plugs

Remark 1

When, during execution of a real-time action, the check detects that the position of the power supply selector plugs does not correspond to the setting data (meaning: Setting data should be executed which were calculated for the other power supply), this error condition holds only for the current beam process. In the next beam process, the data may be correct. This is a sort of temporary (dynamic) error state. A global state like 'interlock' is not adequate for such error states which may rapidly change: An beam process specific error state representation has to be used.

Multiplexing

Equipment will be operated beam-process multiplexed.

HW-Trigger

The bumper needs a precise trigger pulse, activated by the timing System (triggered by a timing-event). The trigger pulse will be generated by the front-end controller crate (SCU crate) which impelements the bumper's FESA-class.

The trigger will be provided via a digital I/O slave card. To assure timing precision, trigger must be generated by hardware only:

• the timing receiver (ECA-unit) must be configured by the FESA-class to generate an appropriate tag on the SCU-bus, triggered by a bumper-start timing-event
• the digital I/O card must be configured to output a pulse on reception of the above listed tag on the SCU-bus

A short introduction into the trigger generation is described in the Wiki-page Timing-Event Based Generation of HW-Triggers.

Internals

• Mockup operates with devices XYR01LB1, XYR01LB2, XYR01LB3, XYR01LB4 on virtual FEC vmla02 - has to be changed to one single power suply (nomenclature needed)
• Hardware programmable via ADC DAC card, more infos on https://www-acc.gsi.de/wiki/Hardware/Intern/AdcDac2Scu#Adressraum
• Usage of FESL (https://www-acc.gsi.de/wiki/FESA/FESA3SupportLibrary) *